diff --git a/sys/xtimer/xtimer.c b/sys/xtimer/xtimer.c
index ff6dccf0f492..17cb8dd30c09 100644
--- a/sys/xtimer/xtimer.c
+++ b/sys/xtimer/xtimer.c
@@ -237,14 +237,16 @@ static void _mutex_timeout(void *arg)
 {
     mutex_thread_t *mt = (mutex_thread_t *)arg;
 
-    mt->timeout = 1;
-    list_node_t *node = list_remove(&mt->mutex->queue,
-                                    (list_node_t *)&mt->thread->rq_entry);
-    if ((node != NULL) && (mt->mutex->queue.next == NULL)) {
-        mt->mutex->queue.next = MUTEX_LOCKED;
+    if (mt->mutex->queue.next != MUTEX_LOCKED) {
+        mt->timeout = 1;
+        list_node_t *node = list_remove(&mt->mutex->queue,
+                                        (list_node_t *)&mt->thread->rq_entry);
+        if ((node != NULL) && (mt->mutex->queue.next == NULL)) {
+            mt->mutex->queue.next = MUTEX_LOCKED;
+        }
+        sched_set_status(mt->thread, STATUS_PENDING);
+        thread_yield_higher();
     }
-    sched_set_status(mt->thread, STATUS_PENDING);
-    thread_yield_higher();
 }
 
 int xtimer_mutex_lock_timeout(mutex_t *mutex, uint64_t timeout)