diff --git a/src/gaxios.ts b/src/gaxios.ts
index 8c6bb0fd..5541e56a 100644
--- a/src/gaxios.ts
+++ b/src/gaxios.ts
@@ -187,13 +187,7 @@ export class Gaxios {
         opts.body = opts.data;
       } else if (typeof opts.data === 'object') {
         opts.body = JSON.stringify(opts.data);
-        if (
-          !Object.keys(opts.headers).some((key: string) =>
-            key.match(/^content-type$/i)
-          )
-        ) {
-          opts.headers['Content-Type'] = 'application/json';
-        }
+        opts.headers['Content-Type'] = 'application/json';
       } else {
         opts.body = opts.data;
       }
diff --git a/test/test.getch.ts b/test/test.getch.ts
index da47708d..3af418b8 100644
--- a/test/test.getch.ts
+++ b/test/test.getch.ts
@@ -307,22 +307,6 @@ describe('🎏 data handling', () => {
     assert.deepStrictEqual(res.data, {});
   });
 
-  it('should allow to override content-type for object request', async () => {
-    const body = {hello: '🌎'};
-    const scope = nock(url)
-      .matchHeader('content-type', 'application/octet-stream')
-      .post('/', JSON.stringify(body))
-      .reply(200, {});
-    const res = await request({
-      url,
-      method: 'POST',
-      data: body,
-      headers: {'content-type': 'application/octet-stream'},
-    });
-    scope.done();
-    assert.deepStrictEqual(res.data, {});
-  });
-
   it('should return stream if asked nicely', async () => {
     const body = {hello: '🌎'};
     const scope = nock(url)