diff --git a/_extensions/embedded_video.py b/_extensions/embedded_video.py
index 2f8829880..1b2826d6e 100644
--- a/_extensions/embedded_video.py
+++ b/_extensions/embedded_video.py
@@ -48,7 +48,7 @@ class IframeVideo(Directive):
 
 
 class Youtube(IframeVideo):
-    html = '<iframe src="http://www.youtube.com/embed/%(video_id)s" \
+    html = '<iframe src="https://www.youtube.com/embed/%(video_id)s" \
     width="%(width)u" height="%(height)u" frameborder="0" \
     webkitAllowFullScreen mozallowfullscreen allowfullscreen \
     class="align-%(align)s"></iframe>'