diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 9c7fa5c9e..bbb411b87 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1412,7 +1412,7 @@ pref("network.http.bypass-cachelock-threshold", 250);
 
 // Try and use SPDY when using SSL
 pref("network.http.spdy.enabled", true);
-pref("network.http.spdy.enabled.v3-1", true);
+pref("network.http.spdy.enabled.v3-1", false);
 pref("network.http.spdy.enabled.http2", true);
 pref("network.http.spdy.enabled.deps", true);
 pref("network.http.spdy.enforce-tls-profile", true);