diff --git a/var/spack/repos/builtin/packages/acfl/package.py b/var/spack/repos/builtin/packages/acfl/package.py
index 9147fa6dc70..4d546e57802 100644
--- a/var/spack/repos/builtin/packages/acfl/package.py
+++ b/var/spack/repos/builtin/packages/acfl/package.py
@@ -31,6 +31,7 @@
     "rhel8": "RHEL-8",
     "rhel9": "RHEL-9",
     "rocky8": "RHEL-8",
+    "rocky9": "RHEL-9",
     "amzn2": "AmazonLinux-2",
     "amzn2023": "AmazonLinux-2023",
 }