diff --git a/.readthedocs.yml b/.readthedocs.yml
index 21d235821..26a44dc41 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -9,3 +9,4 @@ python:
 
 sphinx:
   configuration: docs/conf.py
+  builder: dirhtml
diff --git a/sphinx_rtd_theme/layout.html b/sphinx_rtd_theme/layout.html
index bb0c069a2..9b00d0320 100644
--- a/sphinx_rtd_theme/layout.html
+++ b/sphinx_rtd_theme/layout.html
@@ -51,12 +51,26 @@
 
   {#- CANONICAL URL (deprecated) #}
   {%- if theme_canonical_url and not pageurl %}
-    <link rel="canonical" href="{{ theme_canonical_url }}{{ pagename }}.html"/>
+    <link rel="canonical" href="{{ theme_canonical_url }}{{ pagename }}{% if builder == 'dirhtml' %}/{% else %}.html{% endif %}"/>
   {%- endif -%}
 
-  {#- CANONICAL URL #}
-  {%- if pageurl %}
-    <link rel="canonical" href="{{ pageurl|e }}" />
+  {#-
+    CANONICAL URL
+    NB! pageurl is currently a non-documented template context variable!
+    pageurl implementation: https://www.sphinx-doc.org/en/master/_modules/sphinx/builders/html.html
+  -#}
+  {%- if pageurl -%}
+    {#-
+      pageurl implementation wrongly: adds .html for the dirhtml builder's pageurl
+      Workaround for: https://github.com/sphinx-doc/sphinx/issues/9730
+      Once a fix is released in Sphinx, put an upper bound on the Sphinx version for the workaround
+    -#}
+    {%- if builder == 'dirhtml' and pageurl.endswith('.html') %}
+      {#- This expression trims away .html and adds a / #}
+      <link rel="canonical" href="{{ (pageurl|e)[:-5] }}/" />
+    {%- else %}
+      <link rel="canonical" href="{{ pageurl|e }}" />
+    {%- endif -%}
   {%- endif -%}
 
   {#- JAVASCRIPTS #}