diff --git a/bollux b/bollux
index 668930e..4a8db07 100755
--- a/bollux
+++ b/bollux
@@ -477,7 +477,9 @@ ujoin() { # ujoin URL_ARRAY<name>
 		printf -v URL_ARRAY[0] "%s:" "${URL_ARRAY[1]}"
 	fi
 
-	if ucdef URL_ARRAY[2]; then
+	# Need special casing for file: protocol:
+	# https://datatracker.ietf.org/doc/html/rfc1738#section-3.10
+	if ucdef URL_ARRAY[2] || [[ "${URL_ARRAY[1]}" == file ]]; then
 		printf -v URL_ARRAY[0] "${URL_ARRAY[0]}//%s" "${URL_ARRAY[2]}"
 	fi