diff --git a/esp8266/modules/webrepl.py b/esp8266/modules/webrepl.py
index da3e70c5953460b2eeef3fdd58cd58f5ac21771e..b200f4fc816aa195b7217967c92b434ffce34681 100644
--- a/esp8266/modules/webrepl.py
+++ b/esp8266/modules/webrepl.py
@@ -31,6 +31,10 @@ def setup_conn(port, accept_handler):
 def accept_conn(listen_sock):
     global client_s
     cl, remote_addr = listen_sock.accept()
+    if uos.dupterm():
+        print("\nConcurrent WebREPL connection from", remote_addr, "rejected")
+        cl.close()
+        return
     print("\nWebREPL connection from:", remote_addr)
     client_s = cl
     websocket_helper.server_handshake(cl)