diff --git a/__test__/git-auth-helper.test.ts b/__test__/git-auth-helper.test.ts
index 7633704..a15a7f5 100644
--- a/__test__/git-auth-helper.test.ts
+++ b/__test__/git-auth-helper.test.ts
@@ -796,6 +796,18 @@ async function setup(testName: string): Promise<void> {
     ),
     tryDisableAutomaticGarbageCollection: jest.fn(),
     tryGetFetchUrl: jest.fn(),
+    getSubmoduleConfigPaths: jest.fn(async () => {
+      return []
+    }),
+    tryConfigUnsetValue: jest.fn(async () => {
+      return true
+    }),
+    tryGetConfigValues: jest.fn(async () => {
+      return []
+    }),
+    tryGetConfigKeys: jest.fn(async () => {
+      return []
+    }),
     tryReset: jest.fn(),
     version: jest.fn()
   }
diff --git a/__test__/git-directory-helper.test.ts b/__test__/git-directory-helper.test.ts
index 22e9ae6..1627b84 100644
--- a/__test__/git-directory-helper.test.ts
+++ b/__test__/git-directory-helper.test.ts
@@ -499,6 +499,18 @@ async function setup(testName: string): Promise<void> {
       await fs.promises.stat(path.join(repositoryPath, '.git'))
       return repositoryUrl
     }),
+    getSubmoduleConfigPaths: jest.fn(async () => {
+      return []
+    }),
+    tryConfigUnsetValue: jest.fn(async () => {
+      return true
+    }),
+    tryGetConfigValues: jest.fn(async () => {
+      return []
+    }),
+    tryGetConfigKeys: jest.fn(async () => {
+      return []
+    }),
     tryReset: jest.fn(async () => {
       return true
     }),
diff --git a/dist/index.js b/dist/index.js
index f3ae6f3..0e545db 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -411,8 +411,40 @@ class GitAuthHelper {
     }
     removeToken() {
         return __awaiter(this, void 0, void 0, function* () {
-            // HTTP extra header
+            // Remove HTTP extra header from local git config and submodule configs
             yield this.removeGitConfig(this.tokenConfigKey);
+            //
+            // Cleanup actions/checkout@v6 style credentials
+            //
+            // Collect credentials config paths that need to be removed
+            const credentialsPaths = new Set();
+            // Remove includeIf entries that point to git-credentials-*.config files
+            const mainCredentialsPaths = yield this.removeIncludeIfCredentials();
+            mainCredentialsPaths.forEach(path => credentialsPaths.add(path));
+            // Remove submodule includeIf entries that point to git-credentials-*.config files
+            try {
+                const submoduleConfigPaths = yield this.git.getSubmoduleConfigPaths(true);
+                for (const configPath of submoduleConfigPaths) {
+                    const submoduleCredentialsPaths = yield this.removeIncludeIfCredentials(configPath);
+                    submoduleCredentialsPaths.forEach(path => credentialsPaths.add(path));
+                }
+            }
+            catch (err) {
+                core.debug(`Unable to get submodule config paths: ${err}`);
+            }
+            // Remove credentials config files
+            for (const credentialsPath of credentialsPaths) {
+                // Only remove credentials config files if they are under RUNNER_TEMP
+                const runnerTemp = process.env['RUNNER_TEMP'];
+                if (runnerTemp && credentialsPath.startsWith(runnerTemp)) {
+                    try {
+                        yield io.rmRF(credentialsPath);
+                    }
+                    catch (err) {
+                        core.debug(`Failed to remove credentials config '${credentialsPath}': ${err}`);
+                    }
+                }
+            }
         });
     }
     removeGitConfig(configKey_1) {
@@ -430,6 +462,49 @@ class GitAuthHelper {
             `sh -c "git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :"`, true);
         });
     }
+    /**
+     * Removes includeIf entries that point to git-credentials-*.config files.
+     * This handles cleanup of credentials configured by newer versions of the action.
+     * @param configPath Optional path to a specific git config file to operate on
+     * @returns Array of unique credentials config file paths that were found and removed
+     */
+    removeIncludeIfCredentials(configPath) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const credentialsPaths = new Set();
+            try {
+                // Get all includeIf.gitdir keys
+                const keys = yield this.git.tryGetConfigKeys('^includeIf\\.gitdir:', false, // globalConfig?
+                configPath);
+                for (const key of keys) {
+                    // Get all values for this key
+                    const values = yield this.git.tryGetConfigValues(key, false, // globalConfig?
+                    configPath);
+                    if (values.length > 0) {
+                        // Remove only values that match git-credentials-<uuid>.config pattern
+                        for (const value of values) {
+                            if (this.testCredentialsConfigPath(value)) {
+                                credentialsPaths.add(value);
+                                yield this.git.tryConfigUnsetValue(key, value, false, configPath);
+                            }
+                        }
+                    }
+                }
+            }
+            catch (err) {
+                // Ignore errors - this is cleanup code
+                core.debug(`Error during includeIf cleanup${configPath ? ` for ${configPath}` : ''}: ${err}`);
+            }
+            return Array.from(credentialsPaths);
+        });
+    }
+    /**
+     * Tests if a path matches the git-credentials-*.config pattern used by newer versions.
+     * @param path The path to test
+     * @returns True if the path matches the credentials config pattern
+     */
+    testCredentialsConfigPath(path) {
+        return /git-credentials-[0-9a-f-]+\.config$/i.test(path);
+    }
 }
 
 
@@ -706,6 +781,16 @@ class GitCommandManager {
             throw new Error('Unexpected output when retrieving default branch');
         });
     }
+    getSubmoduleConfigPaths(recursive) {
+        return __awaiter(this, void 0, void 0, function* () {
+            // Get submodule config file paths.
+            // Use `--show-origin` to get the config file path for each submodule.
+            const output = yield this.submoduleForeach(`git config --local --show-origin --name-only --get-regexp remote.origin.url`, recursive);
+            // Extract config file paths from the output (lines starting with "file:").
+            const configPaths = output.match(/(?<=(^|\n)file:)[^\t]+(?=\tremote\.origin\.url)/g) || [];
+            return configPaths;
+        });
+    }
     getWorkingDirectory() {
         return this.workingDirectory;
     }
@@ -836,6 +921,20 @@ class GitCommandManager {
             return output.exitCode === 0;
         });
     }
+    tryConfigUnsetValue(configKey, configValue, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--unset', configKey, configValue);
+            const output = yield this.execGit(args, true);
+            return output.exitCode === 0;
+        });
+    }
     tryDisableAutomaticGarbageCollection() {
         return __awaiter(this, void 0, void 0, function* () {
             const output = yield this.execGit(['config', '--local', 'gc.auto', '0'], true);
@@ -855,6 +954,46 @@ class GitCommandManager {
             return stdout;
         });
     }
+    tryGetConfigValues(configKey, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--get-all', configKey);
+            const output = yield this.execGit(args, true);
+            if (output.exitCode !== 0) {
+                return [];
+            }
+            return output.stdout
+                .trim()
+                .split('\n')
+                .filter(value => value.trim());
+        });
+    }
+    tryGetConfigKeys(pattern, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--name-only', '--get-regexp', pattern);
+            const output = yield this.execGit(args, true);
+            if (output.exitCode !== 0) {
+                return [];
+            }
+            return output.stdout
+                .trim()
+                .split('\n')
+                .filter(key => key.trim());
+        });
+    }
     tryReset() {
         return __awaiter(this, void 0, void 0, function* () {
             const output = yield this.execGit(['reset', '--hard', 'HEAD'], true);
diff --git a/src/git-auth-helper.ts b/src/git-auth-helper.ts
index 126e8e5..272c823 100644
--- a/src/git-auth-helper.ts
+++ b/src/git-auth-helper.ts
@@ -346,8 +346,46 @@ class GitAuthHelper {
   }
 
   private async removeToken(): Promise<void> {
-    // HTTP extra header
+    // Remove HTTP extra header from local git config and submodule configs
     await this.removeGitConfig(this.tokenConfigKey)
+
+    //
+    // Cleanup actions/checkout@v6 style credentials
+    //
+
+    // Collect credentials config paths that need to be removed
+    const credentialsPaths = new Set<string>()
+
+    // Remove includeIf entries that point to git-credentials-*.config files
+    const mainCredentialsPaths = await this.removeIncludeIfCredentials()
+    mainCredentialsPaths.forEach(path => credentialsPaths.add(path))
+
+    // Remove submodule includeIf entries that point to git-credentials-*.config files
+    try {
+      const submoduleConfigPaths = await this.git.getSubmoduleConfigPaths(true)
+      for (const configPath of submoduleConfigPaths) {
+        const submoduleCredentialsPaths =
+          await this.removeIncludeIfCredentials(configPath)
+        submoduleCredentialsPaths.forEach(path => credentialsPaths.add(path))
+      }
+    } catch (err) {
+      core.debug(`Unable to get submodule config paths: ${err}`)
+    }
+
+    // Remove credentials config files
+    for (const credentialsPath of credentialsPaths) {
+      // Only remove credentials config files if they are under RUNNER_TEMP
+      const runnerTemp = process.env['RUNNER_TEMP']
+      if (runnerTemp && credentialsPath.startsWith(runnerTemp)) {
+        try {
+          await io.rmRF(credentialsPath)
+        } catch (err) {
+          core.debug(
+            `Failed to remove credentials config '${credentialsPath}': ${err}`
+          )
+        }
+      }
+    }
   }
 
   private async removeGitConfig(
@@ -371,4 +409,59 @@ class GitAuthHelper {
       true
     )
   }
+
+  /**
+   * Removes includeIf entries that point to git-credentials-*.config files.
+   * This handles cleanup of credentials configured by newer versions of the action.
+   * @param configPath Optional path to a specific git config file to operate on
+   * @returns Array of unique credentials config file paths that were found and removed
+   */
+  private async removeIncludeIfCredentials(
+    configPath?: string
+  ): Promise<string[]> {
+    const credentialsPaths = new Set<string>()
+
+    try {
+      // Get all includeIf.gitdir keys
+      const keys = await this.git.tryGetConfigKeys(
+        '^includeIf\\.gitdir:',
+        false, // globalConfig?
+        configPath
+      )
+
+      for (const key of keys) {
+        // Get all values for this key
+        const values = await this.git.tryGetConfigValues(
+          key,
+          false, // globalConfig?
+          configPath
+        )
+        if (values.length > 0) {
+          // Remove only values that match git-credentials-<uuid>.config pattern
+          for (const value of values) {
+            if (this.testCredentialsConfigPath(value)) {
+              credentialsPaths.add(value)
+              await this.git.tryConfigUnsetValue(key, value, false, configPath)
+            }
+          }
+        }
+      }
+    } catch (err) {
+      // Ignore errors - this is cleanup code
+      core.debug(
+        `Error during includeIf cleanup${configPath ? ` for ${configPath}` : ''}: ${err}`
+      )
+    }
+
+    return Array.from(credentialsPaths)
+  }
+
+  /**
+   * Tests if a path matches the git-credentials-*.config pattern used by newer versions.
+   * @param path The path to test
+   * @returns True if the path matches the credentials config pattern
+   */
+  private testCredentialsConfigPath(path: string): boolean {
+    return /git-credentials-[0-9a-f-]+\.config$/i.test(path)
+  }
 }
diff --git a/src/git-command-manager.ts b/src/git-command-manager.ts
index 8e42a38..9c789ac 100644
--- a/src/git-command-manager.ts
+++ b/src/git-command-manager.ts
@@ -41,6 +41,7 @@ export interface IGitCommandManager {
     }
   ): Promise<void>
   getDefaultBranch(repositoryUrl: string): Promise<string>
+  getSubmoduleConfigPaths(recursive: boolean): Promise<string[]>
   getWorkingDirectory(): string
   init(): Promise<void>
   isDetached(): Promise<boolean>
@@ -59,8 +60,24 @@ export interface IGitCommandManager {
   tagExists(pattern: string): Promise<boolean>
   tryClean(): Promise<boolean>
   tryConfigUnset(configKey: string, globalConfig?: boolean): Promise<boolean>
+  tryConfigUnsetValue(
+    configKey: string,
+    configValue: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<boolean>
   tryDisableAutomaticGarbageCollection(): Promise<boolean>
   tryGetFetchUrl(): Promise<string>
+  tryGetConfigValues(
+    configKey: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]>
+  tryGetConfigKeys(
+    pattern: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]>
   tryReset(): Promise<boolean>
   version(): Promise<GitVersion>
 }
@@ -323,6 +340,21 @@ class GitCommandManager {
     throw new Error('Unexpected output when retrieving default branch')
   }
 
+  async getSubmoduleConfigPaths(recursive: boolean): Promise<string[]> {
+    // Get submodule config file paths.
+    // Use `--show-origin` to get the config file path for each submodule.
+    const output = await this.submoduleForeach(
+      `git config --local --show-origin --name-only --get-regexp remote.origin.url`,
+      recursive
+    )
+
+    // Extract config file paths from the output (lines starting with "file:").
+    const configPaths =
+      output.match(/(?<=(^|\n)file:)[^\t]+(?=\tremote\.origin\.url)/g) || []
+
+    return configPaths
+  }
+
   getWorkingDirectory(): string {
     return this.workingDirectory
   }
@@ -455,6 +487,24 @@ class GitCommandManager {
     return output.exitCode === 0
   }
 
+  async tryConfigUnsetValue(
+    configKey: string,
+    configValue: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<boolean> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--unset', configKey, configValue)
+
+    const output = await this.execGit(args, true)
+    return output.exitCode === 0
+  }
+
   async tryDisableAutomaticGarbageCollection(): Promise<boolean> {
     const output = await this.execGit(
       ['config', '--local', 'gc.auto', '0'],
@@ -481,6 +531,56 @@ class GitCommandManager {
     return stdout
   }
 
+  async tryGetConfigValues(
+    configKey: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--get-all', configKey)
+
+    const output = await this.execGit(args, true)
+
+    if (output.exitCode !== 0) {
+      return []
+    }
+
+    return output.stdout
+      .trim()
+      .split('\n')
+      .filter(value => value.trim())
+  }
+
+  async tryGetConfigKeys(
+    pattern: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--name-only', '--get-regexp', pattern)
+
+    const output = await this.execGit(args, true)
+
+    if (output.exitCode !== 0) {
+      return []
+    }
+
+    return output.stdout
+      .trim()
+      .split('\n')
+      .filter(key => key.trim())
+  }
+
   async tryReset(): Promise<boolean> {
     const output = await this.execGit(['reset', '--hard', 'HEAD'], true)
     return output.exitCode === 0