diff --git a/src/Validator/Constraints/TimezoneValidator.php b/src/Validator/Constraints/TimezoneValidator.php
index d047a99..6c913c3 100644
--- a/src/Validator/Constraints/TimezoneValidator.php
+++ b/src/Validator/Constraints/TimezoneValidator.php
@@ -30,7 +30,8 @@ public function validate(mixed $value, Constraint $constraint): void
 
         $value = $this->getValue($value);
 
-        if (!in_array($value, \DateTimeZone::listIdentifiers(), true)) {
+        // Mirror \DateTimeZone, which also accepts backward-compatible aliases (US/Hawaii).
+        if (!in_array($value, \DateTimeZone::listIdentifiers(\DateTimeZone::ALL_WITH_BC), true)) {
             $this->context->buildViolation($constraint->message)
                 ->setParameter('{{ value }}', $this->formatValue($value))
                 ->setCode(Timezone::NO_SUCH_TIMEZONE_ERROR)
diff --git a/tests/Validator/Constraints/TimezoneValidatorTest.php b/tests/Validator/Constraints/TimezoneValidatorTest.php
index 7c023be..a9c6eaf 100644
--- a/tests/Validator/Constraints/TimezoneValidatorTest.php
+++ b/tests/Validator/Constraints/TimezoneValidatorTest.php
@@ -32,6 +32,21 @@ public function testExpectsStringCompatibleType(): void
         $this->validator->validate(new \stdClass(), new Timezone());
     }
 
+    public function testAcceptsBackwardCompatibleAlias(): void
+    {
+        $aliases = array_diff(
+            \DateTimeZone::listIdentifiers(\DateTimeZone::ALL_WITH_BC),
+            \DateTimeZone::listIdentifiers(),
+        );
+        if ([] === $aliases) {
+            self::markTestSkipped('The timezone database of this platform has no backward-compatible alias.');
+        }
+
+        $this->validator->validate(reset($aliases), new Timezone());
+
+        $this->assertNoViolation();
+    }
+
     public static function providerValidValues(): iterable
     {
         yield [null];
@@ -48,5 +63,10 @@ public static function providerInvalidValues(): iterable
             Timezone::NO_SUCH_TIMEZONE_ERROR,
             'The value {{ value }} is not a valid timezone.',
         ];
+        yield [
+            'US/Atlantis',
+            Timezone::NO_SUCH_TIMEZONE_ERROR,
+            'The value {{ value }} is not a valid timezone.',
+        ];
     }
 }