diff --git a/src/Extension/Autolink/UrlAutolinkParser.php b/src/Extension/Autolink/UrlAutolinkParser.php
index 6b4290a994..29425134f3 100644
--- a/src/Extension/Autolink/UrlAutolinkParser.php
+++ b/src/Extension/Autolink/UrlAutolinkParser.php
@@ -113,9 +113,9 @@ public function parse(InlineParserContext $inlineContext): bool
 
         $cursor->advanceBy(\mb_strlen($url, 'UTF-8'));
 
-        // Auto-prefix 'http://' onto 'www' URLs
+        // Auto-prefix 'https://' onto 'www' URLs
         if (\substr($url, 0, 4) === 'www.') {
-            $inlineContext->getContainer()->appendChild(new Link('http://' . $url, $url));
+            $inlineContext->getContainer()->appendChild(new Link('https://' . $url, $url));
 
             return true;
         }