diff --git a/doc/conf.py b/doc/conf.py
index c1f369c1..b780f82d 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -88,6 +88,11 @@ extensions = [
     "sphinx.ext.extlinks",
 ]
 
+# The search extension works only on readthedocs
+# See https://readthedocs-sphinx-search.readthedocs.io
+if on_rtd:
+    extensions.append("sphinx_search.extension")
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = [doc_path + '/_templates']
 
diff --git a/doc/requirements.txt b/doc/requirements.txt
index e1a4488f..f31b40c3 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1 +1,2 @@
 sphinx-rtd-theme~=1.3.0
+readthedocs-sphinx-search~=0.3.1