diff --git a/_redirects b/_redirects
index 21d1045ad21..8a0fc952efd 100644
--- a/_redirects
+++ b/_redirects
@@ -77,3 +77,7 @@ https://docs.cert-manager.io/en/release-0.16/* https://cert-manager.io/docs/rele
 https://docs.cert-manager.io/en/release-* https://cert-manager.io/docs/release-notes/release-notes-:splat 301!
 https://docs.cert-manager.io https://cert-manager.io/docs 301!
 https://docs.cert-manager.io/* https://cert-manager.io/docs/:splat 302!
+
+# redirect anything else to our custom 404 page. this is required as the site generator / theme uses relative links for the 404 page, which break if the
+# 404 page isn't served from /404.html
+/* /404.html 404