diff --git a/jest.config.ts b/jest.config.ts
index 001e0ef9..d0198e35 100644
--- a/jest.config.ts
+++ b/jest.config.ts
@@ -11,6 +11,8 @@ const config: Config = {
   moduleDirectories: ['node_modules', 'src'],
   preset: 'ts-jest/presets/default-esm',
   setupFilesAfterEnv: ['<rootDir>/test/jest-setup.ts'],
+  globalSetup: '<rootDir>/test/jest-global-setup.ts',
+  globalTeardown: '<rootDir>/test/jest-global-teardown.ts',
   testEnvironment: 'node',
   testRegex: ['.*\\.test\\.ts$'],
   // Tell Jest to ignore the specific duplicate package.json files
diff --git a/test/jest-global-setup.ts b/test/jest-global-setup.ts
new file mode 100644
index 00000000..c0efca91
--- /dev/null
+++ b/test/jest-global-setup.ts
@@ -0,0 +1,20 @@
+const fs = require('fs');
+const path = require('path');
+
+module.exports = async function globalSetup() {
+  const envPath = path.join(process.cwd(), '.env');
+  const backupPath = path.join(process.cwd(), '.env.test-backup');
+
+  // Backup .env file if it exists and clear related env vars
+  if (fs.existsSync(envPath)) {
+    fs.renameSync(envPath, backupPath);
+    console.log('Backed up .env file for testing');
+
+    // Also clear any OCO_ environment variables that might have been loaded
+    Object.keys(process.env).forEach(key => {
+      if (key.startsWith('OCO_')) {
+        delete process.env[key];
+      }
+    });
+  }
+}
diff --git a/test/jest-global-teardown.ts b/test/jest-global-teardown.ts
new file mode 100644
index 00000000..5f741a48
--- /dev/null
+++ b/test/jest-global-teardown.ts
@@ -0,0 +1,13 @@
+const fs = require('fs');
+const path = require('path');
+
+module.exports = async function globalTeardown() {
+  const envPath = path.join(process.cwd(), '.env');
+  const backupPath = path.join(process.cwd(), '.env.test-backup');
+
+  // Restore .env file
+  if (fs.existsSync(backupPath)) {
+    fs.renameSync(backupPath, envPath);
+    console.log('Restored .env file after testing');
+  }
+}
diff --git a/test/unit/config.test.ts b/test/unit/config.test.ts
index fc4709dc..324f7697 100644
--- a/test/unit/config.test.ts
+++ b/test/unit/config.test.ts
@@ -15,7 +15,10 @@ describe('config', () => {
 
   function resetEnv(env: NodeJS.ProcessEnv) {
     Object.keys(process.env).forEach((key) => {
-      if (!(key in env)) {
+      if (key.startsWith('OCO_')) {
+        // Don't restore OCO_ environment variables to avoid test interference
+        delete process.env[key];
+      } else if (!(key in env)) {
         delete process.env[key];
       } else {
         process.env[key] = env[key];
@@ -122,7 +125,7 @@ describe('config', () => {
       expect(config.OCO_ONE_LINE_COMMIT).toEqual(false);
       expect(config.OCO_OMIT_SCOPE).toEqual(true);
     });
-    
+
     it('should handle custom HTTP headers correctly', async () => {
       globalConfigFile = await generateConfig('.opencommit', {
         OCO_API_CUSTOM_HEADERS: '{"X-Global-Header": "global-value"}'
@@ -139,7 +142,7 @@ describe('config', () => {
 
       expect(config).not.toEqual(null);
       expect(config.OCO_API_CUSTOM_HEADERS).toEqual({"Authorization": "Bearer token123", "X-Custom-Header": "test-value"});
-      
+
       // No need to parse JSON again since it's already an object
       const parsedHeaders = config.OCO_API_CUSTOM_HEADERS;
       expect(parsedHeaders).toHaveProperty('Authorization', 'Bearer token123');