diff --git a/docs/csharp/language-reference/operators/sizeof.md b/docs/csharp/language-reference/operators/sizeof.md
index 159618d9bb89e..cc786c042fdec 100644
--- a/docs/csharp/language-reference/operators/sizeof.md
+++ b/docs/csharp/language-reference/operators/sizeof.md
@@ -1,7 +1,7 @@
 ---
 title: "sizeof operator - determine the storage needs for a type"
 description: "Learn about the C# `sizeof` operator that returns the memory amount occupied by a variable of a given type."
-ms.date: 06/16/2026
+ms.date: 06/29/2026
 f1_keywords:
   - "sizeof_CSharpKeyword"
   - "sizeof"
@@ -10,7 +10,7 @@ helpviewer_keywords:
 ---
 # sizeof operator - determine the memory needs for a given type
 
-The `sizeof` operator returns the number of bytes occupied by a variable of a given type. In safe code, the argument to the `sizeof` operator must be the name of a built-in [unmanaged type](../builtin-types/unmanaged-types.md) whose size isn't platform-dependent.
+The `sizeof` operator returns the number of bytes occupied by a variable of a given type. In safe code, the argument to the `sizeof` operator must be the name of a built-in [unmanaged type](../builtin-types/unmanaged-types.md) whose size isn't platform-dependent, or an [enumeration type](../builtin-types/enum.md).
 
 [!INCLUDE[csharp-version-note](../includes/initial-version.md)]
 
@@ -41,6 +41,7 @@ In [unsafe](../keywords/unsafe.md) code, you can use `sizeof` on any non-`void`
 
 - The size of a reference or pointer type is the size of a reference or pointer, not the size of the object it might refer to.
 - The size of a value type, unmanaged or not, is the size of such a value.
+- The size of an enumeration type is the size of its underlying integral type. This size is a compile-time constant. If the underlying type of an enum defined in a referenced assembly later changes, code that applied `sizeof` to that enum must be recompiled to observe the new size.
 - The size of a `ref struct` type is the size of the value. The size of every `ref` field is the size of a reference or pointer, not the size of the value it refers to.
 
 The following example demonstrates the usage of the `sizeof` operator: