diff --git a/jupyterhub/app.py b/jupyterhub/app.py
index 79c5c3ec..b121c265 100644
--- a/jupyterhub/app.py
+++ b/jupyterhub/app.py
@@ -1026,7 +1026,7 @@ class JupyterHub(Application):
         self.log.info("Starting proxy @ %s", self.proxy.public_server.bind_url)
         self.log.debug("Proxy cmd: %s", cmd)
         try:
-            self.proxy_process = Popen(cmd, env=env)
+            self.proxy_process = Popen(cmd, env=env, preexec_fn=os.setpgrp)
         except FileNotFoundError as e:
             self.log.error(
                 "Failed to find proxy %r\n"