diff --git a/Lib/http/client.py b/Lib/http/client.py
index 08cf2ed..a6ab135 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -70,6 +70,7 @@
 
 import email.parser
 import email.message
+import errno
 import http
 import io
 import re
@@ -939,7 +940,12 @@ def connect(self):
         sys.audit("http.client.connect", self, self.host, self.port)
         self.sock = self._create_connection(
             (self.host,self.port), self.timeout, self.source_address)
-        self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+        # Might fail in OSs that don't implement TCP_NODELAY
+        try:
+             self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+        except OSError as e:
+            if e.errno != errno.ENOPROTOOPT:
+                raise
 
         if self._tunnel_host:
             self._tunnel()