diff --git a/bin/gstack-next-version b/bin/gstack-next-version
index 1df13aad8e..dbb7229eed 100755
--- a/bin/gstack-next-version
+++ b/bin/gstack-next-version
@@ -446,11 +446,12 @@ function parseArgs(argv: string[]): { base: string; bump: Bump; current: string;
     console.error("Error: --bump is required (major|minor|patch|micro)");
     process.exit(2);
   }
-  if (!["major", "minor", "patch", "micro"].includes(bump)) {
+  const normalizedBump = bump.toLowerCase();
+  if (!["major", "minor", "patch", "micro"].includes(normalizedBump)) {
     console.error(`Error: --bump must be major|minor|patch|micro (got ${bump})`);
     process.exit(2);
   }
-  return { base, bump: bump as Bump, current, workspaceRoot, excludePR, versionPath, help: false };
+  return { base, bump: normalizedBump as Bump, current, workspaceRoot, excludePR, versionPath, help: false };
 }
 
 // Auto-detect: if --exclude-pr wasn't passed, check whether the current branch
@@ -785,7 +786,7 @@ async function main() {
 // Pure-function exports for testing. The version primitives are re-exported
 // from lib/version-source so existing importers of this module keep working
 // unchanged.
-export { parseVersion, fmtVersion, bumpVersion, cmpVersion, versionWidth, extractVersion };
+export { parseArgs, parseVersion, fmtVersion, bumpVersion, cmpVersion, versionWidth, extractVersion };
 export { pickNextSlot, markActiveSiblings, resolveVersionPath, fetchGitClaimed };
 
 // Only run main() when invoked as a script, not when imported by tests.
diff --git a/test/gstack-next-version.test.ts b/test/gstack-next-version.test.ts
index 9099fd626e..0759889b1e 100644
--- a/test/gstack-next-version.test.ts
+++ b/test/gstack-next-version.test.ts
@@ -9,6 +9,7 @@ import { chmodSync, mkdirSync, mkdtempSync, readFileSync, writeFileSync, rmSync
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import {
+  parseArgs,
   parseVersion,
   fmtVersion,
   bumpVersion,
@@ -21,6 +22,15 @@ import {
   fetchGitClaimed,
 } from "../bin/gstack-next-version";
 
+describe("parseArgs case normalization (#2770)", () => {
+  test("accepts uppercase and mixed-case bump levels", () => {
+    expect(parseArgs(["--base", "main", "--bump", "MICRO"]).bump).toBe("micro");
+    expect(parseArgs(["--base", "main", "--bump", "PATCH"]).bump).toBe("patch");
+    expect(parseArgs(["--base", "main", "--bump", "Minor"]).bump).toBe("minor");
+    expect(parseArgs(["--base", "main", "--bump", "MAJOR"]).bump).toBe("major");
+  });
+});
+
 describe("parseVersion", () => {
   test("accepts 4-digit semver", () => {
     expect(parseVersion("1.6.3.0")).toEqual([1, 6, 3, 0]);