diff --git a/NEWS b/NEWS
index 798f849854c1..85458d81dd94 100644
--- a/NEWS
+++ b/NEWS
@@ -36,6 +36,8 @@ PHP                                                                        NEWS
     (Marti2203).
   . Fixed bug GH-24989 (Use-after-free in GC when an exception is thrown).
     (David Carlier)
+  . Fixed AST export of readonly anonymous classes dropping the readonly
+    modifier. (Jorg Sowa)
 
 - CLI:
   . Fixed bug GH-24697 (PHP_HTTP_PARSER_STRICT build option doesn't work).
diff --git a/Zend/tests/assert/expect_readonly_anon_class.phpt b/Zend/tests/assert/expect_readonly_anon_class.phpt
new file mode 100644
index 000000000000..5944475ffc4e
--- /dev/null
+++ b/Zend/tests/assert/expect_readonly_anon_class.phpt
@@ -0,0 +1,22 @@
+--TEST--
+AST export of readonly anonymous class
+--INI--
+zend.assertions=1
+--FILE--
+<?php
+try {
+    assert(false && new readonly class {});
+} catch (AssertionError $e) {
+    echo $e::class, ': ', $e->getMessage(), "\n";
+}
+try {
+    assert(false && new #[A] readonly class(1) {});
+} catch (AssertionError $e) {
+    echo $e::class, ': ', $e->getMessage(), "\n";
+}
+?>
+--EXPECT--
+AssertionError: assert(false && new readonly class {
+})
+AssertionError: assert(false && new #[A] readonly class(1) {
+})
diff --git a/Zend/zend_ast.c b/Zend/zend_ast.c
index 4e640a321d1f..f3031bbc930d 100644
--- a/Zend/zend_ast.c
+++ b/Zend/zend_ast.c
@@ -2311,6 +2311,9 @@ static ZEND_COLD void zend_ast_export_ex(smart_str *str, zend_ast *ast, int prio
 				if (decl->child[3]) {
 					zend_ast_export_attributes(str, decl->child[3], indent, 0);
 				}
+				if (decl->flags & ZEND_ACC_READONLY_CLASS) {
+					smart_str_appends(str, "readonly ");
+				}
 				smart_str_appends(str, "class");
 				if (!zend_ast_is_list(ast->child[1])
 						|| zend_ast_get_list(ast->child[1])->children) {