diff --git a/src/civetweb.c b/src/civetweb.c
index c83bd96f..d777f3f9 100644
--- a/src/civetweb.c
+++ b/src/civetweb.c
@@ -5326,12 +5326,12 @@ static void close_socket_gracefully(struct mg_connection *conn)
 
 static void close_connection(struct mg_connection *conn)
 {
-    mg_lock(conn);
-
     // call the connection_close callback if assigned
     if (conn->ctx->callbacks.connection_close != NULL)
         conn->ctx->callbacks.connection_close(conn);
 
+    mg_lock(conn);
+
     conn->must_close = 1;
 
 #ifndef NO_SSL