diff --git a/doc/requirements.txt b/doc/requirements.txt
index 89437ca..344457f 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -6,6 +6,7 @@ sphinxcontrib-applehelp==1.0.4
 sphinxcontrib-bibtex==2.4.2
 sphinxcontrib-devhelp==1.0.2
 sphinxcontrib-htmlhelp==2.0.1
+sphinxcontrib-serializinghtml==1.1.5
 pygments-github-lexers==0.0.5
 pennylane>=0.22,<0.34
 sphinx-automodapi==0.14.1