diff --git a/lib/http/client.rb b/lib/http/client.rb
index e6e03a5d..7643403a 100644
--- a/lib/http/client.rb
+++ b/lib/http/client.rb
@@ -51,7 +51,7 @@ def perform(req, options)
 
       # TODO: keep-alive support
       @socket = options[:socket_class].open(req.socket_host, req.socket_port)
-      @socket = start_tls(@socket, options) if uri.is_a?(URI::HTTPS)
+      @socket = start_tls(@socket, options) if uri.is_a?(URI::HTTPS) && !req.using_proxy?
 
       req.stream @socket