diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index dd96f9aa62b85b..fe9d6fe2763f36 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -1132,7 +1132,9 @@ _curses_window_addstr_impl(PyCursesWindowObject *self, int group_left_1,
     else
 #endif
     {
+#ifdef HAVE_NCURSESW
         assert(wstr == NULL);
+#endif
         const char *str = PyBytes_AS_STRING(bytesobj);
         if (use_xy) {
             rtn = mvwaddstr(self->win,y,x,str);