diff --git a/rpyc/core/protocol.py b/rpyc/core/protocol.py
index dfd6f4a4..76cc80f6 100644
--- a/rpyc/core/protocol.py
+++ b/rpyc/core/protocol.py
@@ -396,8 +396,7 @@ def _recv(self, timeout, wait_for_lock):
             self._recvlock.release()
         return data
 
-    def _dispatch(self, data):
-        msg, seq, args = brine.load(data)
+    def _dispatch(self, msg, seq, args):
         if msg == consts.MSG_REQUEST:
             self._dispatch_request(seq, args)
         elif msg == consts.MSG_REPLY:
@@ -416,11 +415,21 @@ def sync_recv_and_dispatch(self, timeout, wait_for_lock):
                 data = self._recv(timeout, wait_for_lock=wait_for_lock)
                 if not data:
                     return False
-                self._dispatch(data)
-                return True
+
+                msg, seq, args = brine.load(data)
+                # Have to enqueue to _sync_replies before releasing _recvlock to
+                # avoid race conditions with other threads
+                sync_reply = (msg in (consts.MSG_REPLY, consts.MSG_EXCEPTION) and
+                              seq not in self._async_callbacks)
+                if sync_reply:
+                    self._dispatch(msg, seq, args)
+                    return True
+
             finally:
                 self._sync_lock.release()
                 self._sync_event.set()
+            self._dispatch(msg, seq, args)
+            return True
         else:
             return self._sync_event.wait(
                 timeout.timeleft() if timeout.finite else None)