diff --git a/node-src/lib/getDependentStoryFiles.ts b/node-src/lib/getDependentStoryFiles.ts
index 851356324..5c85aa0ff 100644
--- a/node-src/lib/getDependentStoryFiles.ts
+++ b/node-src/lib/getDependentStoryFiles.ts
@@ -4,6 +4,7 @@ import { Context, Module, Reason, Stats } from '../types';
 import noCSFGlobs from '../ui/messages/errors/noCSFGlobs';
 import tracedAffectedFiles from '../ui/messages/info/tracedAffectedFiles';
 import bailFile from '../ui/messages/warnings/bailFile';
+import { posix } from './posix';
 import { isPackageManifestFile, matchesFile } from './utils';
 
 type FilePath = string;
@@ -27,11 +28,6 @@ const isUserModule = (module_: Module | Reason) =>
   (module_ as Module).id !== null &&
   !INTERNALS.some((re) => re.test((module_ as Module).name || (module_ as Reason).moduleName));
 
-// Replaces Windows-style backslash path separators with POSIX-style forward slashes, because the
-// Webpack stats use forward slashes in the `name` and `moduleName` fields. Note `changedFiles`
-// already contains forward slashes, because that's what git yields even on Windows.
-const posix = (localPath: string) => localPath.split(path.sep).filter(Boolean).join(path.posix.sep);
-
 // For any path in node_modules, return the package name, including scope prefix if any.
 const getPackageName = (modulePath: string) => {
   const [, scopedName] = modulePath.match(/\/node_modules\/(@[\w-]+\/[\w-]+)\//) || [];
@@ -90,7 +86,7 @@ export async function getDependentStoryFiles(
   }
 
   const {
-    baseDir: storybookBaseDirectory = '',
+    baseDir: baseDirectory = '',
     configDir: configDirectory = '.storybook',
     staticDir: staticDirectory = [],
     viewLayer,
@@ -102,8 +98,6 @@ export async function getDependentStoryFiles(
     untraced = [],
   } = ctx.options;
 
-  const baseDirectory = posix(storybookBaseDirectory);
-
   // Convert a "webpack path" (relative to storybookBaseDir) to a "git path" (relative to repository root)
   // e.g. `./src/file.js` => `path/to/storybook/src/file.js`
   const normalize = (posixPath: FilePath): NormalizedName => {
diff --git a/node-src/lib/getStorybookBaseDirectory.test.ts b/node-src/lib/getStorybookBaseDirectory.test.ts
index 3581f0068..e727ab98e 100644
--- a/node-src/lib/getStorybookBaseDirectory.test.ts
+++ b/node-src/lib/getStorybookBaseDirectory.test.ts
@@ -1,11 +1,20 @@
+import path from 'node:path';
 import process from 'node:process';
 
-import { expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
 import { Context } from '../types';
 import { getStorybookBaseDirectory } from './getStorybookBaseDirectory';
 
 const mockedCwd = vi.spyOn(process, 'cwd');
+const mockedRelative = vi.spyOn(path, 'relative');
+const mockedJoin = vi.spyOn(path, 'join');
+
+// The definition of posix depends on `path.sep` being correct for the system
+// (ie.equal to `\\` for windows), however we can't really mock that as it's a constant
+vi.mock('./posix', () => ({
+  posix: (localPath: string) => localPath.split('\\').filter(Boolean).join('/'),
+}));
 
 it('defaults to the configured value', () => {
   expect(getStorybookBaseDirectory({ options: { storybookBaseDir: 'foobar' } } as Context)).toBe(
@@ -40,3 +49,22 @@ it('falls back the empty string if there is no git root', () => {
 
   expect(getStorybookBaseDirectory({} as Context)).toBe('.');
 });
+
+describe('with windows paths', () => {
+  beforeEach(() => {
+    mockedRelative.mockImplementation(path.win32.relative);
+    mockedJoin.mockImplementation(path.win32.join);
+  });
+
+  afterEach(() => {
+    mockedRelative.mockRestore();
+    mockedJoin.mockRestore();
+  });
+
+  it('uses posix paths even if we are windows', () => {
+    const rootPath = String.raw`C:\path\to\project`;
+    mockedCwd.mockReturnValue(String.raw`${rootPath}\storybook\subdir`);
+
+    expect(getStorybookBaseDirectory({ git: { rootPath } } as Context)).toBe('storybook/subdir');
+  });
+});
diff --git a/node-src/lib/getStorybookBaseDirectory.ts b/node-src/lib/getStorybookBaseDirectory.ts
index a00e1efe7..9e9ed6d48 100644
--- a/node-src/lib/getStorybookBaseDirectory.ts
+++ b/node-src/lib/getStorybookBaseDirectory.ts
@@ -1,6 +1,7 @@
 import path from 'path';
 
 import { Context } from '../types';
+import { posix } from './posix';
 
 /**
  * Get the storybook base directory, relative to the git root.
@@ -24,5 +25,5 @@ export function getStorybookBaseDirectory(ctx: Context) {
   // NOTE:
   //  - path.relative does not have a leading '.', unless it starts with '../'
   //  - path.join('.', '') === '.' and path.join('.', '../x') = '../x'
-  return path.join('.', path.relative(rootPath, ''));
+  return posix(path.join('.', path.relative(rootPath, '')));
 }
diff --git a/node-src/lib/posix.ts b/node-src/lib/posix.ts
new file mode 100644
index 000000000..48ba80cfa
--- /dev/null
+++ b/node-src/lib/posix.ts
@@ -0,0 +1,7 @@
+import path from 'path';
+
+// Replaces Windows-style backslash path separators with POSIX-style forward slashes, because the
+// Webpack stats use forward slashes in the `name` and `moduleName` fields. Note `changedFiles`
+// already contains forward slashes, because that's what git yields even on Windows.
+export const posix = (localPath: string) =>
+  localPath.split(path.sep).filter(Boolean).join(path.posix.sep);