diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1aaa30b..40d91ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.7.0] -
 
 ### Fixed
+- **`Async\signal()` no longer dies in worker threads** (#109). Each call to
+  `php_request_startup()` in a worker thread ran `zend_signal_activate()`,
+  which unconditionally re-installed `zend_signal_handler_defer` via
+  `sigaction()` — clobbering the libuv handler the reactor had installed in
+  the main thread. The next process-directed signal then hit Zend's defer
+  path in a worker whose `SIGG(handlers)` was empty, fell through to
+  `SIG_DFL`, and killed the process. Fixed in `Zend/zend_signal.c`:
+  `zend_signal_activate()` and `zend_signal_deactivate()` now early-return
+  when `zend_async_reactor_is_enabled()` (reactor module registered at
+  MINIT) — the reactor owns the OS-level sigaction process-wide, and the
+  per-thread libuv signal callback already dispatches via TLS `SIGG(handlers)`.
+  `zend_sigaction` is unchanged so pcntl-only flows keep working. Tests
+  `tests/signal/008-009` cover both `ThreadPool` and `spawn_thread` variants.
 - **PDO MySQL `010-pdo_resource_cleanup` no longer false-fails under
   parallel test workers** (#114). The test counted leaks against
   `SHOW STATUS LIKE 'Threads_connected'` — a *server-global* counter that
diff --git a/tests/signal/008-signal_thread_pool_multi.phpt b/tests/signal/008-signal_thread_pool_multi.phpt
new file mode 100644
index 0000000..ae331bb
--- /dev/null
+++ b/tests/signal/008-signal_thread_pool_multi.phpt
@@ -0,0 +1,59 @@
+--TEST--
+Async\signal() #109: multiple workers in ThreadPool each receive process-directed signal
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') echo "skip Unix-only test";
+if (!function_exists('posix_kill')) echo "skip posix extension required";
+if (!PHP_ZTS) echo "skip ZTS required";
+?>
+--FILE--
+<?php
+
+use Async\Signal;
+use Async\ThreadPool;
+use function Async\signal;
+use function Async\spawn;
+use function Async\await;
+use function Async\timeout;
+use function Async\delay;
+
+echo "start\n";
+
+$pool = new ThreadPool(workers: 2);
+
+$f1 = $pool->submit(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR1), timeout(2000));
+        return "w1:" . $r->name;
+    } catch (\Throwable $e) {
+        return "w1:ex:" . $e->getMessage();
+    }
+});
+
+$f2 = $pool->submit(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR1), timeout(2000));
+        return "w2:" . $r->name;
+    } catch (\Throwable $e) {
+        return "w2:ex:" . $e->getMessage();
+    }
+});
+
+spawn(function () {
+    delay(300);
+    posix_kill(getmypid(), SIGUSR1);
+});
+
+$results = [await($f1), await($f2)];
+sort($results);
+foreach ($results as $r) echo $r . "\n";
+
+$pool->close();
+echo "end\n";
+
+?>
+--EXPECT--
+start
+w1:SIGUSR1
+w2:SIGUSR1
+end
diff --git a/tests/signal/009-signal_spawn_thread_multi.phpt b/tests/signal/009-signal_spawn_thread_multi.phpt
new file mode 100644
index 0000000..862ed38
--- /dev/null
+++ b/tests/signal/009-signal_spawn_thread_multi.phpt
@@ -0,0 +1,56 @@
+--TEST--
+Async\signal() #109: multiple spawn_thread workers each receive process-directed signal
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') echo "skip Unix-only test";
+if (!function_exists('posix_kill')) echo "skip posix extension required";
+if (!PHP_ZTS) echo "skip ZTS required";
+?>
+--FILE--
+<?php
+
+use Async\Signal;
+use function Async\signal;
+use function Async\spawn;
+use function Async\spawn_thread;
+use function Async\await;
+use function Async\timeout;
+use function Async\delay;
+
+echo "start\n";
+
+$t1 = spawn_thread(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR1), timeout(2000));
+        return "t1:" . $r->name;
+    } catch (\Throwable $e) {
+        return "t1:ex:" . $e->getMessage();
+    }
+});
+
+$t2 = spawn_thread(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR1), timeout(2000));
+        return "t2:" . $r->name;
+    } catch (\Throwable $e) {
+        return "t2:ex:" . $e->getMessage();
+    }
+});
+
+spawn(function () {
+    delay(300);
+    posix_kill(getmypid(), SIGUSR1);
+});
+
+$results = [await($t1), await($t2)];
+sort($results);
+foreach ($results as $r) echo $r . "\n";
+
+echo "end\n";
+
+?>
+--EXPECT--
+start
+t1:SIGUSR1
+t2:SIGUSR1
+end
diff --git a/tests/signal/010-signal_unregistered_kills_process.phpt b/tests/signal/010-signal_unregistered_kills_process.phpt
new file mode 100644
index 0000000..773b24f
--- /dev/null
+++ b/tests/signal/010-signal_unregistered_kills_process.phpt
@@ -0,0 +1,44 @@
+--TEST--
+Async\signal() #109: unregistered SIGINT/SIGTERM still kill the process at OS level
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') echo "skip Unix-only test";
+if (!extension_loaded('pcntl')) echo "skip pcntl required";
+if (!extension_loaded('posix')) echo "skip posix required";
+?>
+--EXTENSIONS--
+pcntl
+posix
+--FILE--
+<?php
+// Verify: a PHP process with TrueAsync loaded but no registered handler
+// for SIGINT/SIGTERM is killed by the signal exactly as the OS default
+// action says. The patch in Zend/zend_signal.c must not change this —
+// Ctrl-C semantics for unhandled signals are preserved.
+//
+// pcntl_fork + pcntl_waitpid gives us reliable WIFSIGNALED/WTERMSIG info.
+
+function check(int $signum, string $name): void {
+    $pid = pcntl_fork();
+    if ($pid === 0) {
+        // child: just sleep — no signal handlers registered
+        usleep(3_000_000);
+        exit(0);
+    }
+    usleep(200_000);
+    posix_kill($pid, $signum);
+    pcntl_waitpid($pid, $status);
+    $sig = pcntl_wifsignaled($status) ? pcntl_wtermsig($status) : 0;
+    echo "$name: ", ($sig === $signum ? "killed by $name" : "FAIL exit_sig=$sig"), "\n";
+}
+
+check(SIGINT,  'SIGINT');
+check(SIGTERM, 'SIGTERM');
+check(SIGUSR1, 'SIGUSR1');
+echo "done\n";
+?>
+--EXPECT--
+SIGINT: killed by SIGINT
+SIGTERM: killed by SIGTERM
+SIGUSR1: killed by SIGUSR1
+done
diff --git a/tests/signal/011-signal_pcntl_still_works.phpt b/tests/signal/011-signal_pcntl_still_works.phpt
new file mode 100644
index 0000000..6d05d85
--- /dev/null
+++ b/tests/signal/011-signal_pcntl_still_works.phpt
@@ -0,0 +1,31 @@
+--TEST--
+Async\signal() #109: pcntl_signal still intercepts when TrueAsync is loaded
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') echo "skip Unix-only test";
+if (!extension_loaded('pcntl')) echo "skip pcntl required";
+if (!extension_loaded('posix')) echo "skip posix required";
+?>
+--EXTENSIONS--
+pcntl
+posix
+--FILE--
+<?php
+// Verify: pcntl_signal() goes through zend_sigaction (which the patch
+// does NOT touch) and still receives the signal correctly even though
+// zend_signal_activate is a no-op under TrueAsync.
+
+$got = null;
+pcntl_signal(SIGUSR1, function (int $signo) use (&$got) {
+    $got = $signo;
+});
+
+posix_kill(posix_getpid(), SIGUSR1);
+pcntl_signal_dispatch();
+
+echo "got=", var_export($got, true), "\n";
+echo $got === SIGUSR1 ? "OK\n" : "FAIL\n";
+?>
+--EXPECT--
+got=10
+OK
diff --git a/tests/signal/012-signal_thread_pool_different_signals.phpt b/tests/signal/012-signal_thread_pool_different_signals.phpt
new file mode 100644
index 0000000..a967e24
--- /dev/null
+++ b/tests/signal/012-signal_thread_pool_different_signals.phpt
@@ -0,0 +1,64 @@
+--TEST--
+Async\signal() #109: ThreadPool workers can register different signals concurrently
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') echo "skip Unix-only test";
+if (!function_exists('posix_kill')) echo "skip posix extension required";
+if (!PHP_ZTS) echo "skip ZTS required";
+?>
+--FILE--
+<?php
+// Each worker waits for a *different* signal. The main thread fires both
+// signals; each worker must receive its own and only its own. This
+// validates that per-thread libuv signal handles are independent and
+// that signal dispatch routes by signo, not by "first registered".
+
+use Async\Signal;
+use Async\ThreadPool;
+use function Async\signal;
+use function Async\spawn;
+use function Async\await;
+use function Async\timeout;
+use function Async\delay;
+
+echo "start\n";
+
+$pool = new ThreadPool(workers: 2);
+
+$f1 = $pool->submit(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR1), timeout(2000));
+        return "w1:" . $r->name;
+    } catch (\Throwable $e) {
+        return "w1:ex:" . $e->getMessage();
+    }
+});
+
+$f2 = $pool->submit(function () {
+    try {
+        $r = await(signal(Signal::SIGUSR2), timeout(2000));
+        return "w2:" . $r->name;
+    } catch (\Throwable $e) {
+        return "w2:ex:" . $e->getMessage();
+    }
+});
+
+spawn(function () {
+    delay(300);
+    posix_kill(getmypid(), SIGUSR1);
+    posix_kill(getmypid(), SIGUSR2);
+});
+
+$results = [await($f1), await($f2)];
+sort($results);
+foreach ($results as $r) echo $r . "\n";
+
+$pool->close();
+echo "end\n";
+
+?>
+--EXPECT--
+start
+w1:SIGUSR1
+w2:SIGUSR2
+end