diff --git a/.changeset/fix-zod-discriminated-union-multi-value.md b/.changeset/fix-zod-discriminated-union-multi-value.md
new file mode 100644
index 0000000000..90b83b0597
--- /dev/null
+++ b/.changeset/fix-zod-discriminated-union-multi-value.md
@@ -0,0 +1,5 @@
+---
+'@hey-api/openapi-ts': patch
+---
+
+fix(zod): generate z.discriminatedUnion when discriminator maps multiple values to the same schema
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b3327ba5b3
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBar = z.object({
+    code: z.optional(z.union([z.literal(1), z.literal(2)]))
+});
+
+export const zBaz = z.object({
+    code: z.optional(z.literal(3))
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    z.extend(zBar, { code: z.union([z.literal(1), z.literal(2)]) }),
+    z.extend(zBaz, { code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..a7e388b534
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBar = z.object({
+    foo: z.optional(z.enum(['one', 'two']))
+});
+
+export const zBaz = z.object({
+    foo: z.optional(z.enum(['three']))
+});
+
+export const zSpæcial = z.object({
+    foo: z.optional(z.enum(['four']))
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    z.extend(zBar, { foo: z.enum(['one', 'two']) }),
+    z.extend(zBaz, { foo: z.literal('three') }),
+    z.extend(zSpæcial, { foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b9fa614597
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,17 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.literal(1) }),
+    zBar.extend({ code: z.literal(2) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..5b51ab9abe
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..0417778aea
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.union([z.literal(1), z.literal(2)]) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..9994b91a08
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b3327ba5b3
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBar = z.object({
+    code: z.optional(z.union([z.literal(1), z.literal(2)]))
+});
+
+export const zBaz = z.object({
+    code: z.optional(z.literal(3))
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    z.extend(zBar, { code: z.union([z.literal(1), z.literal(2)]) }),
+    z.extend(zBaz, { code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..a7e388b534
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBar = z.object({
+    foo: z.optional(z.enum(['one', 'two']))
+});
+
+export const zBaz = z.object({
+    foo: z.optional(z.enum(['three']))
+});
+
+export const zSpæcial = z.object({
+    foo: z.optional(z.enum(['four']))
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    z.extend(zBar, { foo: z.enum(['one', 'two']) }),
+    z.extend(zBaz, { foo: z.literal('three') }),
+    z.extend(zSpæcial, { foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b9fa614597
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,17 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.literal(1) }),
+    zBar.extend({ code: z.literal(2) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..5b51ab9abe
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..0417778aea
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.union([z.literal(1), z.literal(2)]) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..9994b91a08
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts b/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
index f498a05473..d2418c0cb3 100644
--- a/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
@@ -34,6 +34,22 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'generates circular schemas',
       },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many.yaml',
+          output: 'discriminator-mapped-many',
+        }),
+        description:
+          'generates discriminated union when multiple mapping values point to same schema',
+      },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many-number.yaml',
+          output: 'discriminator-mapped-many-number',
+        }),
+        description:
+          'generates discriminated union when multiple number mapping values point to same schema',
+      },
       {
         config: createConfig({
           input: 'enum-null.json',
diff --git a/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts b/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
index 5761d3ba64..ed01c96e5f 100644
--- a/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
@@ -152,6 +152,22 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'handles oneOf discriminator (falls back to z.union when needed)',
       },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many.yaml',
+          output: 'discriminator-mapped-many',
+        }),
+        description:
+          'generates discriminated union when multiple mapping values point to same schema',
+      },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many-number.yaml',
+          output: 'discriminator-mapped-many-number',
+        }),
+        description:
+          'generates discriminated union when multiple number mapping values point to same schema',
+      },
       {
         config: createConfig({
           input: 'enum-null.json',
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..5fc0bdc133
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBar = z.object({
+    code: z.optional(z.union([z.literal(1), z.literal(2)]))
+});
+
+export const zBaz = z.object({
+    code: z.optional(z.literal(3))
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    z.extend(zBar, { code: z.union([z.literal(1), z.literal(2)]) }),
+    z.extend(zBaz, { code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..a365be0f13
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBar = z.object({
+    foo: z.optional(z.enum(['one', 'two']))
+});
+
+export const zBaz = z.object({
+    foo: z.optional(z.enum(['three']))
+});
+
+export const zSpæcial = z.object({
+    foo: z.optional(z.enum(['four']))
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    z.extend(zBar, { foo: z.enum(['one', 'two']) }),
+    z.extend(zBaz, { foo: z.literal('three') }),
+    z.extend(zSpæcial, { foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..e8fbc4a26e
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,17 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.literal(1) }),
+    zBar.extend({ code: z.literal(2) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..1b25c19cad
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b11c5e2390
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.union([z.literal(1), z.literal(2)]) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..facaac6e38
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..5fc0bdc133
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBar = z.object({
+    code: z.optional(z.union([z.literal(1), z.literal(2)]))
+});
+
+export const zBaz = z.object({
+    code: z.optional(z.literal(3))
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    z.extend(zBar, { code: z.union([z.literal(1), z.literal(2)]) }),
+    z.extend(zBaz, { code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..a365be0f13
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBar = z.object({
+    foo: z.optional(z.enum(['one', 'two']))
+});
+
+export const zBaz = z.object({
+    foo: z.optional(z.enum(['three']))
+});
+
+export const zSpæcial = z.object({
+    foo: z.optional(z.enum(['four']))
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    z.extend(zBar, { foo: z.enum(['one', 'two']) }),
+    z.extend(zBaz, { foo: z.literal('three') }),
+    z.extend(zSpæcial, { foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..e8fbc4a26e
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,17 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.literal(1) }),
+    zBar.extend({ code: z.literal(2) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..1b25c19cad
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts
new file mode 100644
index 0000000000..b11c5e2390
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many-number/zod.gen.ts
@@ -0,0 +1,16 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod';
+
+export const zBar = z.object({
+    code: z.union([z.literal(1), z.literal(2)]).optional()
+});
+
+export const zBaz = z.object({
+    code: z.literal(3).optional()
+});
+
+export const zFoo = z.discriminatedUnion('code', [
+    zBar.extend({ code: z.union([z.literal(1), z.literal(2)]) }),
+    zBaz.extend({ code: z.literal(3) })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts
new file mode 100644
index 0000000000..facaac6e38
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/discriminator-mapped-many/zod.gen.ts
@@ -0,0 +1,21 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod';
+
+export const zBar = z.object({
+    foo: z.enum(['one', 'two']).optional()
+});
+
+export const zBaz = z.object({
+    foo: z.enum(['three']).optional()
+});
+
+export const zSpæcial = z.object({
+    foo: z.enum(['four']).optional()
+});
+
+export const zFoo = z.discriminatedUnion('foo', [
+    zBar.extend({ foo: z.enum(['one', 'two']) }),
+    zBaz.extend({ foo: z.literal('three') }),
+    zSpæcial.extend({ foo: z.literal('four') })
+]);
diff --git a/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts b/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
index 18659712b5..0d004290f3 100644
--- a/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
@@ -42,6 +42,22 @@ for (const zodVersion of zodVersions) {
         description:
           'falls back to z.union() when discriminated union members have allOf (intersection)',
       },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many.yaml',
+          output: 'discriminator-mapped-many',
+        }),
+        description:
+          'generates discriminated union when multiple mapping values point to same schema',
+      },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many-number.yaml',
+          output: 'discriminator-mapped-many-number',
+        }),
+        description:
+          'generates discriminated union when multiple number mapping values point to same schema',
+      },
       {
         config: createConfig({
           input: 'enum-null.json',
diff --git a/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts b/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
index 703c51f7ab..3232387292 100644
--- a/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
@@ -185,6 +185,22 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'handles oneOf discriminator (falls back to z.union when needed)',
       },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many.yaml',
+          output: 'discriminator-mapped-many',
+        }),
+        description:
+          'generates discriminated union when multiple mapping values point to same schema',
+      },
+      {
+        config: createConfig({
+          input: 'discriminator-mapped-many-number.yaml',
+          output: 'discriminator-mapped-many-number',
+        }),
+        description:
+          'generates discriminated union when multiple number mapping values point to same schema',
+      },
       {
         config: createConfig({
           input: 'enum-null.json',
diff --git a/packages/openapi-ts/src/plugins/zod/mini/toAst/union.ts b/packages/openapi-ts/src/plugins/zod/mini/toAst/union.ts
index 183ce382c8..4efb5b83ee 100644
--- a/packages/openapi-ts/src/plugins/zod/mini/toAst/union.ts
+++ b/packages/openapi-ts/src/plugins/zod/mini/toAst/union.ts
@@ -2,7 +2,10 @@ import { $ } from '../../../../ts-dsl';
 import { identifiers } from '../../constants';
 import type { UnionResolverContext } from '../../resolvers';
 import type { Chain } from '../../shared/chain';
-import { tryBuildDiscriminatedUnion } from '../../shared/discriminated-union';
+import {
+  buildDiscriminatorExpression,
+  tryBuildDiscriminatedUnion,
+} from '../../shared/discriminated-union';
 import type { ZodResult } from '../../shared/types';
 
 type UnionToAstOptions = Pick<
@@ -42,6 +45,9 @@ function baseNode(ctx: UnionResolverContext): Chain {
   });
 
   if (discriminatedExpression) {
+    // z.discriminatedUnion requires each branch discriminator to be a type that
+    // z.discriminatedUnion's internal getDiscriminator can extract a value from.
+    // See buildDiscriminatorExpression for the three cases handled.
     const unionMembers = discriminatedExpression.members.map((member) =>
       $(z)
         .attr(identifiers.extend)
@@ -49,7 +55,7 @@ function baseNode(ctx: UnionResolverContext): Chain {
           member.refExpression,
           $.object().prop(
             discriminatedExpression.discriminatorKey,
-            $(z).attr(identifiers.literal).call($.fromValue(member.discriminatedValue)),
+            buildDiscriminatorExpression(z, member.discriminatedValue),
           ),
         ),
     );
diff --git a/packages/openapi-ts/src/plugins/zod/shared/discriminated-union.ts b/packages/openapi-ts/src/plugins/zod/shared/discriminated-union.ts
index 4e85cc1a13..685c2705df 100644
--- a/packages/openapi-ts/src/plugins/zod/shared/discriminated-union.ts
+++ b/packages/openapi-ts/src/plugins/zod/shared/discriminated-union.ts
@@ -1,7 +1,8 @@
-import type { SymbolMeta } from '@hey-api/codegen-core';
+import type { Symbol, SymbolMeta } from '@hey-api/codegen-core';
 import type { IR } from '@hey-api/shared';
 
 import { $ } from '../../../ts-dsl';
+import { identifiers } from '../constants';
 import type { ZodPlugin } from '../types';
 import type { Chain } from './chain';
 import type { ZodMeta, ZodResult } from './types';
@@ -40,7 +41,22 @@ export function tryBuildDiscriminatedUnion({
     if (schema.logicalOperator !== 'and' || !schema.items || schema.items.length !== 2) return null;
 
     const refPart = schema.items[1]!;
-    const discriminatedValue = schema.items[0]!.properties?.[discriminatorKey]?.const;
+    const discriminatorProp = schema.items[0]!.properties?.[discriminatorKey];
+    let discriminatedValue: unknown;
+    if (discriminatorProp?.const !== undefined) {
+      // Single const value — the common case: { type: "cat" }
+      discriminatedValue = discriminatorProp.const;
+    } else if (
+      discriminatorProp?.logicalOperator === 'or' &&
+      discriminatorProp.items?.length &&
+      discriminatorProp.items.every((item) => item.const !== undefined)
+    ) {
+      // OR-of-consts — the discriminator maps multiple values to one schema.
+      // Every item must have a const; a future IR change that violates this would
+      // silently fall through to `discriminatedValue === undefined` below, which
+      // degrades the output from z.discriminatedUnion to a plain z.union.
+      discriminatedValue = discriminatorProp.items.map((item) => item.const);
+    }
 
     // lazy references can't be used in a discriminated union directly
     if (discriminatedValue === undefined || items[index]!.meta.hasLazy) return null;
@@ -75,3 +91,34 @@ export function tryBuildDiscriminatedUnion({
     members,
   };
 }
+
+/**
+ * Builds the Zod AST node for a discriminator branch value.
+ *
+ * Zod's discriminatedUnion requires each branch discriminator to be a type that
+ * getDiscriminator can extract a value set from (ZodLiteral, ZodEnum, or in v4+
+ * ZodUnion of literals). The shape to emit depends on the value:
+ *
+ *   "cat"       → z.literal("cat")
+ *   ["x"]       → z.literal("x")         single-element: literal is more ergonomic
+ *   ["a", "b"]  → z.enum(["a", "b"])     all strings: enum is more ergonomic than union
+ *   [1, 2]      → z.union([z.literal(1), z.literal(2)])
+ */
+export function buildDiscriminatorExpression(z: Symbol, value: unknown): Chain {
+  if (!Array.isArray(value)) {
+    return $(z).attr(identifiers.literal).call($.fromValue(value));
+  }
+
+  // Single-element array: prefer z.literal over a single-item enum/union
+  if (value.length === 1) {
+    return $(z).attr(identifiers.literal).call($.fromValue(value[0]));
+  }
+
+  if (value.length > 0 && value.every((v) => typeof v === 'string')) {
+    return $(z).attr(identifiers.enum).call($.fromValue(value));
+  }
+
+  return $(z)
+    .attr(identifiers.union)
+    .call($.array(...value.map((v) => $(z).attr(identifiers.literal).call($.fromValue(v)))));
+}
diff --git a/packages/openapi-ts/src/plugins/zod/v3/toAst/union.ts b/packages/openapi-ts/src/plugins/zod/v3/toAst/union.ts
index d588b84f28..13b58c744b 100644
--- a/packages/openapi-ts/src/plugins/zod/v3/toAst/union.ts
+++ b/packages/openapi-ts/src/plugins/zod/v3/toAst/union.ts
@@ -2,7 +2,10 @@ import { $ } from '../../../../ts-dsl';
 import { identifiers } from '../../constants';
 import type { UnionResolverContext } from '../../resolvers';
 import type { Chain } from '../../shared/chain';
-import { tryBuildDiscriminatedUnion } from '../../shared/discriminated-union';
+import {
+  buildDiscriminatorExpression,
+  tryBuildDiscriminatedUnion,
+} from '../../shared/discriminated-union';
 import type { ZodResult } from '../../shared/types';
 
 type UnionToAstOptions = Pick<
@@ -42,16 +45,41 @@ function baseNode(ctx: UnionResolverContext): Chain {
   });
 
   if (discriminatedExpression) {
-    const unionMembers = discriminatedExpression.members.map((member) =>
-      member.refExpression
-        .attr(identifiers.extend)
-        .call(
-          $.object().prop(
-            discriminatedExpression.discriminatorKey,
-            $(z).attr(identifiers.literal).call($.fromValue(member.discriminatedValue)),
+    // getDiscriminator in zod v3 only recognises ZodLiteral and ZodEnum — ZodUnion
+    // is not supported. When a member maps multiple non-string values to one schema,
+    // expand it into one branch per literal so every entry resolves to a ZodLiteral.
+    //   [1, 2]      → two branches: extend({ code: z.literal(1) }), extend({ code: z.literal(2) })
+    //   ["a", "b"]  → one branch:   extend({ code: z.enum(["a", "b"]) })   (ZodEnum is fine)
+    //   "cat"       → one branch:   extend({ code: z.literal("cat") })
+    const unionMembers = discriminatedExpression.members.flatMap((member) => {
+      const isNonStringArray =
+        Array.isArray(member.discriminatedValue) &&
+        !member.discriminatedValue.every((v) => typeof v === 'string');
+
+      if (isNonStringArray) {
+        return (member.discriminatedValue as unknown[]).map((v) =>
+          member.refExpression
+            .attr(identifiers.extend)
+            .call(
+              $.object().prop(
+                discriminatedExpression.discriminatorKey,
+                $(z).attr(identifiers.literal).call($.fromValue(v)),
+              ),
+            ),
+        );
+      }
+
+      return [
+        member.refExpression
+          .attr(identifiers.extend)
+          .call(
+            $.object().prop(
+              discriminatedExpression.discriminatorKey,
+              buildDiscriminatorExpression(z, member.discriminatedValue),
+            ),
           ),
-        ),
-    );
+      ];
+    });
 
     return $(z)
       .attr(identifiers.discriminatedUnion)
diff --git a/packages/openapi-ts/src/plugins/zod/v4/toAst/union.ts b/packages/openapi-ts/src/plugins/zod/v4/toAst/union.ts
index 7ec7667344..d0754838ae 100644
--- a/packages/openapi-ts/src/plugins/zod/v4/toAst/union.ts
+++ b/packages/openapi-ts/src/plugins/zod/v4/toAst/union.ts
@@ -2,7 +2,10 @@ import { $ } from '../../../../ts-dsl';
 import { identifiers } from '../../constants';
 import type { UnionResolverContext } from '../../resolvers';
 import type { Chain } from '../../shared/chain';
-import { tryBuildDiscriminatedUnion } from '../../shared/discriminated-union';
+import {
+  buildDiscriminatorExpression,
+  tryBuildDiscriminatedUnion,
+} from '../../shared/discriminated-union';
 import type { ZodResult } from '../../shared/types';
 
 type UnionToAstOptions = Pick<
@@ -40,13 +43,16 @@ function baseNode(ctx: UnionResolverContext): Chain {
     });
 
     if (discriminatedExpression) {
+      // In v4-native, z.union([z.literal(1), z.literal(2)]) is a valid discriminator
+      // branch because $ZodDiscriminatedUnion derives per-branch values via
+      // option._zod.values, which flattens through ZodUnion of literals.
       const unionMembers = discriminatedExpression.members.map((member) =>
         member.refExpression
           .attr(identifiers.extend)
           .call(
             $.object().prop(
               discriminatedExpression.discriminatorKey,
-              $(z).attr(identifiers.literal).call($.fromValue(member.discriminatedValue)),
+              buildDiscriminatorExpression(z, member.discriminatedValue),
             ),
           ),
       );
diff --git a/specs/3.0.x/discriminator-mapped-many-number.yaml b/specs/3.0.x/discriminator-mapped-many-number.yaml
new file mode 100644
index 0000000000..6c5fc9e8ba
--- /dev/null
+++ b/specs/3.0.x/discriminator-mapped-many-number.yaml
@@ -0,0 +1,31 @@
+openapi: 3.0.0
+info:
+  title: OpenAPI 3.0.0 discriminator mapped many (number) example
+  version: 1
+components:
+  schemas:
+    Foo:
+      oneOf:
+        - $ref: '#/components/schemas/Bar'
+        - $ref: '#/components/schemas/Baz'
+      discriminator:
+        propertyName: code
+        mapping:
+          '1': '#/components/schemas/Bar'
+          '2': '#/components/schemas/Bar'
+          '3': '#/components/schemas/Baz'
+    Bar:
+      type: object
+      properties:
+        code:
+          type: integer
+          enum:
+            - 1
+            - 2
+    Baz:
+      type: object
+      properties:
+        code:
+          type: integer
+          enum:
+            - 3
diff --git a/specs/3.1.x/discriminator-mapped-many-number.yaml b/specs/3.1.x/discriminator-mapped-many-number.yaml
new file mode 100644
index 0000000000..54fa8ae32e
--- /dev/null
+++ b/specs/3.1.x/discriminator-mapped-many-number.yaml
@@ -0,0 +1,31 @@
+openapi: 3.1.0
+info:
+  title: OpenAPI 3.1.0 discriminator mapped many (number) example
+  version: 1
+components:
+  schemas:
+    Foo:
+      oneOf:
+        - $ref: '#/components/schemas/Bar'
+        - $ref: '#/components/schemas/Baz'
+      discriminator:
+        propertyName: code
+        mapping:
+          '1': '#/components/schemas/Bar'
+          '2': '#/components/schemas/Bar'
+          '3': '#/components/schemas/Baz'
+    Bar:
+      type: object
+      properties:
+        code:
+          type: integer
+          enum:
+            - 1
+            - 2
+    Baz:
+      type: object
+      properties:
+        code:
+          type: integer
+          enum:
+            - 3