diff --git a/docs/conf.py b/docs/conf.py
index 8b5658349..3620b2744 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -105,6 +105,7 @@
     r"https://browsersl.ist/#",
     # Ignore unreliable sites
     r"https://web.archive.org/",
+    r"https://www.gnu.org/",  # Consider removal when upgrading Sphinx
     r"http://z3c.pt",  # fluke where Sphinx interprets this as a URL
 ]
 linkcheck_allowed_redirects = {