diff --git a/.changeset/beige-ghosts-enjoy.md b/.changeset/beige-ghosts-enjoy.md
new file mode 100644
index 0000000000..49ae916939
--- /dev/null
+++ b/.changeset/beige-ghosts-enjoy.md
@@ -0,0 +1,5 @@
+---
+'@backstage/cli': minor
+---
+
+The `repo test` command will no longer default to watch mode if the `--since` flag is provided.
diff --git a/packages/cli/src/commands/repo/test.ts b/packages/cli/src/commands/repo/test.ts
index c55969d696..c2a31c1129 100644
--- a/packages/cli/src/commands/repo/test.ts
+++ b/packages/cli/src/commands/repo/test.ts
@@ -172,7 +172,11 @@ export async function command(opts: OptionValues, cmd: Command): Promise<void> {
   }
 
   // Run in watch mode unless in CI, coverage mode, or running all tests
-  if (!process.env.CI && !hasFlags('--coverage', '--watch', '--watchAll')) {
+  if (
+    !opts.since &&
+    !process.env.CI &&
+    !hasFlags('--coverage', '--watch', '--watchAll')
+  ) {
     const isGitRepo = () =>
       runCheck('git', 'rev-parse', '--is-inside-work-tree');
     const isMercurialRepo = () => runCheck('hg', '--cwd', '.', 'root');