diff --git a/ci/build-src-tarball.sh b/ci/build-src-tarball.sh
index ad7e5c916c..4856e6805e 100755
--- a/ci/build-src-tarball.sh
+++ b/ci/build-src-tarball.sh
@@ -4,8 +4,8 @@ set -ex
 
 # Determine the name of the tarball
 tag=dev
-if [[ $GITHUB_REF == refs/tags/v* ]]; then
-  tag=${GITHUB_REF#refs/tags/}
+if [[ $GITHUB_REF == refs/heads/release-* ]]; then
+  tag=v${GITHUB_REF:19}
 fi
 pkgname=wasmtime-$tag-src