diff --git a/environment.yml b/environment.yml
index af2bd1a5829e..a36247dc925a 100644
--- a/environment.yml
+++ b/environment.yml
@@ -43,6 +43,7 @@ dependencies:
   - joblib  # needed for sphinx-gallery[parallel]
   - sphinx-design
   - sphinx-tags>=0.4.0
+  - pystemmer
   - pip
   - pip:
       - mpl-sphinx-theme~=3.8.0
diff --git a/requirements/doc/doc-requirements.txt b/requirements/doc/doc-requirements.txt
index 66f941c763fe..77cb606130b0 100644
--- a/requirements/doc/doc-requirements.txt
+++ b/requirements/doc/doc-requirements.txt
@@ -17,6 +17,7 @@ packaging>=20
 pydata-sphinx-theme~=0.15.0
 mpl-sphinx-theme~=3.9.0
 pyyaml
+PyStemmer
 sphinxcontrib-svg2pdfconverter>=1.1.0
 sphinxcontrib-video>=0.2.1
 sphinx-copybutton