diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 25b8904b1..052ec377e 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -415,7 +415,7 @@ func NewContext() {
 	case "duoshuo":
 		GravatarSource = "http://gravatar.duoshuo.com/avatar/"
 	case "gravatar":
-		GravatarSource = "//secure.gravatar.com/avatar/"
+		GravatarSource = "https://secure.gravatar.com/avatar/"
 	default:
 		GravatarSource = source
 	}