diff --git a/src/shared/setup-runner-command.test.ts b/src/shared/setup-runner-command.test.ts
new file mode 100644
index 00000000000..3362e890c2b
--- /dev/null
+++ b/src/shared/setup-runner-command.test.ts
@@ -0,0 +1,13 @@
+import { describe, expect, it } from 'vitest'
+import { buildSetupRunnerCommand } from './setup-runner-command'
+
+describe('buildSetupRunnerCommand', () => {
+  it('uses bash for WSL UNC runner scripts regardless of host casing', () => {
+    expect(
+      buildSetupRunnerCommand(
+        '\\\\WSL.LOCALHOST\\Ubuntu\\home\\jin\\repo\\.git\\worktrees\\feature\\orca\\setup-runner.sh',
+        'windows'
+      )
+    ).toBe('bash /home/jin/repo/.git/worktrees/feature/orca/setup-runner.sh')
+  })
+})
diff --git a/src/shared/setup-runner-command.ts b/src/shared/setup-runner-command.ts
index fd7b80184d5..95f12d73724 100644
--- a/src/shared/setup-runner-command.ts
+++ b/src/shared/setup-runner-command.ts
@@ -20,12 +20,12 @@ export function buildSetupRunnerCommand(
 
 function isWslUncPath(path: string): boolean {
   const normalized = path.replace(/\\/g, '/')
-  return /^\/\/(wsl\.localhost|wsl\$)\//.test(normalized)
+  return /^\/\/(wsl\.localhost|wsl\$)\//i.test(normalized)
 }
 
 function wslUncToLinuxPath(windowsPath: string): string {
   const normalized = windowsPath.replace(/\\/g, '/')
-  const match = normalized.match(/^\/\/(wsl\.localhost|wsl\$)\/[^/]+(\/.*)?$/)
+  const match = normalized.match(/^\/\/(wsl\.localhost|wsl\$)\/[^/]+(\/.*)?$/i)
   return match?.[2] || '/'
 }