diff --git a/Python/ast.c b/Python/ast.c
index 8414c74..29b0e82 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -131,9 +131,14 @@
 {
     if (!strcmp(x, "None"))
         return ast_error(n, "assignment to None");
-    if (Py_Py3kWarningFlag && !(strcmp(x, "True") && strcmp(x, "False")) &&
-        !ast_warn(c, n, "assignment to True or False is forbidden in 3.x"))
-        return 0;
+    if (Py_Py3kWarningFlag) {
+        if (!(strcmp(x, "True") && strcmp(x, "False")) &&
+            !ast_warn(c, n, "assignment to True or False is forbidden in 3.x"))
+            return 0;
+        if (!strcmp(x, "nonlocal") &&
+            !ast_warn(c, n, "nonlocal is a keyword in 3.x"))
+            return 0;
+    }
     return 1;
 }