diff --git a/__test__/git-auth-helper.test.ts b/__test__/git-auth-helper.test.ts
index e14e948..cf42627 100644
--- a/__test__/git-auth-helper.test.ts
+++ b/__test__/git-auth-helper.test.ts
@@ -738,6 +738,8 @@ async function setup(testName: string): Promise<void> {
     }),
     submoduleSync: jest.fn(),
     submoduleUpdate: jest.fn(),
+    submoduleReset: jest.fn(),
+    submoduleClean: jest.fn(),
     tagExists: jest.fn(),
     tryClean: jest.fn(),
     tryConfigUnset: jest.fn(
diff --git a/__test__/git-directory-helper.test.ts b/__test__/git-directory-helper.test.ts
index 70849b5..e6d3cd0 100644
--- a/__test__/git-directory-helper.test.ts
+++ b/__test__/git-directory-helper.test.ts
@@ -423,6 +423,8 @@ async function setup(testName: string): Promise<void> {
     submoduleForeach: jest.fn(),
     submoduleSync: jest.fn(),
     submoduleUpdate: jest.fn(),
+    submoduleReset: jest.fn(),
+    submoduleClean: jest.fn(),
     tagExists: jest.fn(),
     tryClean: jest.fn(async () => {
       return true
diff --git a/dist/index.js b/dist/index.js
index 271b054..4ed111f 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -7109,6 +7109,26 @@ class GitCommandManager {
             yield this.execGit(args);
         });
     }
+    submoduleReset(recursive) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['submodule', 'foreach'];
+            if (recursive) {
+                args.push('--recursive');
+            }
+            args.push('git reset --hard');
+            yield this.execGit(args);
+        });
+    }
+    submoduleClean(recursive) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['submodule', 'foreach'];
+            if (recursive) {
+                args.push('--recursive');
+            }
+            args.push('git clean -ffdx');
+            yield this.execGit(args);
+        });
+    }
     tagExists(pattern) {
         return __awaiter(this, void 0, void 0, function* () {
             const output = yield this.execGit(['tag', '--list', pattern]);
@@ -7420,6 +7440,11 @@ function getSource(settings) {
                     core.startGroup('Setting up auth for fetching submodules');
                     yield authHelper.configureGlobalAuth();
                     core.endGroup();
+                    // Clean existing submodules
+                    if (settings.clean) {
+                        yield git.submoduleReset(settings.nestedSubmodules);
+                        yield git.submoduleClean(settings.nestedSubmodules);
+                    }
                     // Checkout submodules
                     core.startGroup('Fetching submodules');
                     yield git.submoduleSync(settings.nestedSubmodules);
diff --git a/src/git-command-manager.ts b/src/git-command-manager.ts
index 699a963..faacc21 100644
--- a/src/git-command-manager.ts
+++ b/src/git-command-manager.ts
@@ -41,6 +41,8 @@ export interface IGitCommandManager {
   submoduleForeach(command: string, recursive: boolean): Promise<string>
   submoduleSync(recursive: boolean): Promise<void>
   submoduleUpdate(fetchDepth: number, recursive: boolean): Promise<void>
+  submoduleReset(recursive: boolean): Promise<void>
+  submoduleClean(recursive: boolean): Promise<void>
   tagExists(pattern: string): Promise<boolean>
   tryClean(): Promise<boolean>
   tryConfigUnset(configKey: string, globalConfig?: boolean): Promise<boolean>
@@ -326,6 +328,26 @@ class GitCommandManager {
     await this.execGit(args)
   }
 
+  async submoduleReset(recursive: boolean): Promise<void> {
+    const args = ['submodule', 'foreach']
+    if (recursive) {
+      args.push('--recursive')
+    }
+    args.push('git reset --hard')
+
+    await this.execGit(args)
+  }
+
+  async submoduleClean(recursive: boolean): Promise<void> {
+    const args = ['submodule', 'foreach']
+    if (recursive) {
+      args.push('--recursive')
+    }
+    args.push('git clean -ffdx')
+
+    await this.execGit(args)
+  }
+
   async tagExists(pattern: string): Promise<boolean> {
     const output = await this.execGit(['tag', '--list', pattern])
     return !!output.stdout.trim()
diff --git a/src/git-source-provider.ts b/src/git-source-provider.ts
index 42a12e0..a96afba 100644
--- a/src/git-source-provider.ts
+++ b/src/git-source-provider.ts
@@ -176,6 +176,13 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
         await authHelper.configureGlobalAuth()
         core.endGroup()
 
+        // Clean existing submodules
+        if (settings.clean)
+        {
+            await git.submoduleReset(settings.nestedSubmodules)
+            await git.submoduleClean(settings.nestedSubmodules)
+        }
+
         // Checkout submodules
         core.startGroup('Fetching submodules')
         await git.submoduleSync(settings.nestedSubmodules)