diff --git a/src/Supervisor.php b/src/Supervisor.php
index 03864611..156e60de 100644
--- a/src/Supervisor.php
+++ b/src/Supervisor.php
@@ -222,7 +222,8 @@ public function terminate($status = 0)
         });
 
         if ($this->shouldWait()) {
-            while ($this->processPools->map->runningProcesses()->collapse()->count()) {
+            while ($this->processPools->map->runningProcesses()->collapse()->isNotEmpty()
+                || $this->terminatingProcesses()->isNotEmpty()) {
                 sleep(1);
             }
         }