diff --git a/src/type1/t1load.c b/src/type1/t1load.c
index 53d2a4a6f..e4187c9c9 100644
--- a/src/type1/t1load.c
+++ b/src/type1/t1load.c
@@ -765,7 +765,7 @@
   static
   int  is_alpha( FT_Byte  c )
   {
-    return ( isalnum( c ) || c == '.' || c == '_' );
+    return ( isalnum( c ) || c == '.' || c == '_' || c == '-' );
   }