diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -571,6 +571,8 @@
                    timeout=timeout)
         self.network_event_loop.close()
         self.join(timeout)
+        # Safe to remove event loop.
+        NetworkThread.network_event_loop = None
 
 
 class P2PDataStore(P2PInterface):