diff --git a/asciidoc.nanorc b/asciidoc.nanorc
index 9de3c6f..de486ed 100644
--- a/asciidoc.nanorc
+++ b/asciidoc.nanorc
@@ -1,4 +1,4 @@
-syntax "asciidoc" "\.(asc|asciidoc)$"
+syntax "asciidoc" "\.(asc|asciidoc|adoc)$"
 
 # main header
 color red "^====+$"