diff --git a/slugify.sh b/slugify.sh
index be37349..a7ec44e 100755
--- a/slugify.sh
+++ b/slugify.sh
@@ -28,12 +28,12 @@ else
 fi
 
 slug() {
-  output=$(sed -E 's#refs/[^\/]*/##;s/[^a-zA-Z0-9._]+/-/g;s/-+/-/g;s/^-*//;s/-*$//' <<<"$1")
+  output=$(sed -E 's#refs/[^\/]*/##;s/[^a-zA-Z0-9._-]+/-/g;s/-+/-/g;s/^-*//;s/-*$//' <<<"$1")
   reduce "$output"
 }
 
 slug_url() {
-  output=$(sed -E 's#refs/[^\/]*/##;s/[^a-zA-Z0-9_]+/-/g;s/-+/-/g;s/^-*//;s/-*$//' <<<"$1")
+  output=$(sed -E 's#refs/[^\/]*/##;s/[^a-zA-Z0-9_-]+/-/g;s/-+/-/g;s/^-*//;s/-*$//' <<<"$1")
   reduce "$output"
 }