diff --git a/execnet/gateway_base.py b/execnet/gateway_base.py
index 5db185fb..83c23e90 100644
--- a/execnet/gateway_base.py
+++ b/execnet/gateway_base.py
@@ -116,7 +116,7 @@ def start(self, func, args=()):
     def fdopen(self, fd, mode, bufsize=1):
         import os
 
-        return os.fdopen(fd, mode, bufsize)
+        return os.fdopen(fd, mode, bufsize, encoding="utf-8")
 
     def Lock(self):
         import threading