diff --git a/.changeset/honest-radios-cut.md b/.changeset/honest-radios-cut.md
new file mode 100644
index 0000000000..07a8438cbc
--- /dev/null
+++ b/.changeset/honest-radios-cut.md
@@ -0,0 +1,5 @@
+---
+"@pnpm/find-workspace-dir": patch
+---
+
+Throw an error message if a `.pnpm-workspace.yaml` or `.pnpm-workspace.yml` file is found instead of a `pnpm-workspace.yaml`.
diff --git a/pnpm/test/monorepo/index.ts b/pnpm/test/monorepo/index.ts
index a25cdd1a3d..07339ca830 100644
--- a/pnpm/test/monorepo/index.ts
+++ b/pnpm/test/monorepo/index.ts
@@ -61,19 +61,31 @@ test('no projects found', async () => {
   }
 })
 
-test('incorrect workspace manifest', async () => {
-  preparePackages([
-    {
-      name: 'project',
-      version: '1.0.0',
-    },
-  ])
+const invalidWorkspaceManifests = [
+  'pnpm-workspaces.yaml',
+  'pnpm-workspaces.yml',
+  'pnpm-workspace.yml',
+  '.pnpm-workspaces.yaml',
+  '.pnpm-workspaces.yml',
+  '.pnpm-workspace.yml',
+  '.pnpm-workspace.yaml',
+]
 
-  writeYamlFile('pnpm-workspace.yml', { packages: ['**', '!store/**'] })
+invalidWorkspaceManifests.forEach((filename) => {
+  test('incorrect workspace manifest ' + filename, async () => {
+    preparePackages([
+      {
+        name: 'project',
+        version: '1.0.0',
+      },
+    ])
 
-  const { status, stderr } = execPnpmSync(['install'])
-  expect(stderr.toString()).toMatch(/The workspace manifest file should be named "pnpm-workspace.yaml"/)
-  expect(status).toBe(1)
+    writeYamlFile(filename, { packages: ['**', '!store/**'] })
+
+    const { status, stderr } = execPnpmSync(['install'])
+    expect(stderr.toString()).toMatch(/The workspace manifest file should be named "pnpm-workspace.yaml"/)
+    expect(status).toBe(1)
+  })
 })
 
 test('linking a package inside a monorepo with --link-workspace-packages when installing new dependencies', async () => {
diff --git a/workspace/find-workspace-dir/src/index.ts b/workspace/find-workspace-dir/src/index.ts
index 480d6f01fa..f98f36d7ab 100644
--- a/workspace/find-workspace-dir/src/index.ts
+++ b/workspace/find-workspace-dir/src/index.ts
@@ -5,7 +5,15 @@ import findUp from 'find-up'
 
 const WORKSPACE_DIR_ENV_VAR = 'NPM_CONFIG_WORKSPACE_DIR'
 const WORKSPACE_MANIFEST_FILENAME = 'pnpm-workspace.yaml'
-const INVALID_WORKSPACE_MANIFEST_FILENAME = ['pnpm-workspaces.yaml', 'pnpm-workspaces.yml', 'pnpm-workspace.yml']
+const INVALID_WORKSPACE_MANIFEST_FILENAME = [
+  'pnpm-workspaces.yaml',
+  'pnpm-workspaces.yml',
+  'pnpm-workspace.yml',
+  '.pnpm-workspace.yaml',
+  '.pnpm-workspace.yml',
+  '.pnpm-workspaces.yaml',
+  '.pnpm-workspaces.yml',
+]
 
 export async function findWorkspaceDir (cwd: string): Promise<string | undefined> {
   const workspaceManifestDirEnvVar = process.env[WORKSPACE_DIR_ENV_VAR] ?? process.env[WORKSPACE_DIR_ENV_VAR.toLowerCase()]