diff --git a/CHANGES.rst b/CHANGES.rst
index 49cfd0b..3c7f263 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,7 +5,7 @@
 4.4 (unreleased)
 ================
 
-- Nothing changed yet.
+- Extend boolean html attribute list to include all html5 boolean attributes.
 
 
 4.3 (2024-02-01)
diff --git a/src/z3c/pt/pagetemplate.py b/src/z3c/pt/pagetemplate.py
index 7345ab9..8de71cd 100644
--- a/src/z3c/pt/pagetemplate.py
+++ b/src/z3c/pt/pagetemplate.py
@@ -43,18 +43,40 @@
         # form <img ismap>, as required by XML 1.0.
         # From https://www.w3.org/TR/xhtml1/#C_10 and
         # https://www.w3.org/TR/xhtml1/#h-4.5
+        # Updated to also include html5 attributes as listed on
+        # https://html.spec.whatwg.org/multipage/indices.html#attributes-3
+        "allowfullscreen",
+        "async",
+        "autofocus",
+        "autoplay",
+        "checked",
         "compact",
-        "nowrap",
-        "ismap",
+        "controls",
         "declare",
-        "noshade",
-        "checked",
+        "default",
+        "defer",
         "disabled",
-        "readonly",
+        "formnovalidate",
+        "inert",
+        "ismap",
+        "itemscope",
+        "loop",
         "multiple",
-        "selected",
+        "muted",
+        "nomodule",
         "noresize",
-        "defer",
+        "noshade",
+        "novalidate",
+        "nowrap",
+        "open",
+        "playsinline",
+        "readonly",
+        "required",
+        "reversed",
+        "selected",
+        "shadowrootclonable",
+        "shadowrootdelegatesfocus",
+        "shadowrootserializable",
     ]
 )