diff --git a/utils/build_doc b/utils/build_doc
index d74d8892..db60391a 100755
--- a/utils/build_doc
+++ b/utils/build_doc
@@ -7,6 +7,11 @@ if [ ! -e "setup.py" ]; then
 	exit
 fi
 
+if [ -z "${SECRET_PEERINGDB_API_KEY}" ]; then
+    echo "SECRET_PEERINGDB_API_KEY must be set, but it isn't."
+    exit
+fi
+
 export PYTHONPATH="`pwd`"
 ROOT="`pwd`"