diff --git a/websocket.go b/websocket.go
index 522b88e3..fcc72fc5 100644
--- a/websocket.go
+++ b/websocket.go
@@ -22,7 +22,8 @@ func headerContains(header http.Header, name string, value string) bool {
 
 func isWebSocketRequest(r *http.Request) bool {
 	return headerContains(r.Header, "Connection", "upgrade") &&
-		headerContains(r.Header, "Upgrade", "websocket")
+		( headerContains(r.Header, "Upgrade", "websocket") ||
+			headerContains(r.Header, "Upgrade", "SPDY/3.1"))
 }
 
 func (proxy *ProxyHttpServer) serveWebsocketTLS(ctx *ProxyCtx, w http.ResponseWriter, req *http.Request, tlsConfig *tls.Config, clientConn *tls.Conn) {