diff --git a/notfound/extension.py b/notfound/extension.py
index d038478..cbedee7 100644
--- a/notfound/extension.py
+++ b/notfound/extension.py
@@ -189,7 +189,10 @@ def clear_doc(self, app, env, docname):
         return None
 
     def process_doc(self, app, doctree):
-        app.env.metadata[app.config.notfound_pagename].update({'orphan': True})
+        metadata = app.env.metadata[app.config.notfound_pagename]
+        metadata.update({'orphan': True})
+        if sphinx.version_info >= (3, 0, 0):
+            metadata.update({'nosearch': True})
 
 
 def setup(app):
diff --git a/tests/test_urls.py b/tests/test_urls.py
index 6095378..e6e7d1a 100644
--- a/tests/test_urls.py
+++ b/tests/test_urls.py
@@ -579,4 +579,7 @@ def test_toctree_links_language_setting_version_environment(environ, app, status
 )
 def test_automatic_orphan(app, status, warning):
     app.build()
-    assert app.env.metadata['404'] == {'orphan': True}
+    if sphinx.version_info >= (3, 0, 0):
+        assert app.env.metadata['404'] == {'orphan': True, 'nosearch': True}
+    else:
+        assert app.env.metadata['404'] == {'orphan': True}