diff --git a/dlls/opengl32/wgl.c b/dlls/opengl32/wgl.c
index 1365d6ce96e..2dd59a8f2fe 100644
--- a/dlls/opengl32/wgl.c
+++ b/dlls/opengl32/wgl.c
@@ -94,6 +94,7 @@ static Wine_GLContext *context_list;
 static inline Wine_GLContext *get_context_from_GLXContext(GLXContext ctx)
 {
     Wine_GLContext *ret;
+    if (!ctx) return NULL;
     for (ret = context_list; ret; ret = ret->next) if (ctx == ret->ctx) break;
     return ret;
 }