diff --git a/sys/include/xtimer.h b/sys/include/xtimer.h
index 76b00e4233..44b334ddd9 100644
--- a/sys/include/xtimer.h
+++ b/sys/include/xtimer.h
@@ -410,7 +410,7 @@ static inline bool xtimer_less64(xtimer_ticks64_t a, xtimer_ticks64_t b);
  * @param[in]    us     timeout in microseconds relative
  *
  * @return       0, when returned after mutex was locked
- * @return       -1, when the timeout occcured
+ * @return       -1, when the timeout occurred
  */
 int xtimer_mutex_lock_timeout(mutex_t *mutex, uint64_t us);
 
@@ -421,7 +421,7 @@ int xtimer_mutex_lock_timeout(mutex_t *mutex, uint64_t us);
  * @param[in]    us     timeout in microseconds relative
  *
  * @return       0, when returned after rmutex was locked
- * @return       -1, when the timeout occcured
+ * @return       -1, when the timeout occurred
  */
 int xtimer_rmutex_lock_timeout(rmutex_t *rmutex, uint64_t us);