--- a/netwerk/base/nsSocketTransportService2.cpp
+++ b/netwerk/base/nsSocketTransportService2.cpp
@@ -1062,17 +1062,22 @@ nsSocketTransportService::Run()
 
     // detach all sockets, including locals
     Reset(false);
 
     // Final pass over the event queue. This makes sure that events posted by
     // socket detach handlers get processed.
     NS_ProcessPendingEvents(mRawThread);
 
+    // Stopping the SLL threads can generate new events, so we need to
+    // process them before nulling out gSocketThread, otherwise we can get
+    // !onSocketThread assertions.
     psm::StopSSLServerCertVerificationThreads();
+    NS_ProcessPendingEvents(mRawThread);
+
     gSocketThread = nullptr;
 
     SOCKET_LOG(("STS thread exit\n"));
 
     return NS_OK;
 }
 
 void