diff --git a/quizler/lib.py b/quizler/lib.py
index 28c3ea1..c8ba2b1 100644
--- a/quizler/lib.py
+++ b/quizler/lib.py
@@ -14,12 +14,14 @@ def get_api_envs():
     return client_id, user_id
 
 
-def api_call(method: str, end_point: str, params: Dict[str, str], client_id: str):
+def api_call(method: str, end_point: str, params: Dict[str, str], client_id: str,
+             access_token: str = None):
     """Call given API end_point with API keys."""
     url = 'https://api.quizlet.com/2.0/{}'.format(end_point)
     params['client_id'] = client_id
+    headers = {'Authorization': 'Bearer {}'.format(access_token)} if access_token else None
     # pylint: disable=too-many-function-args
-    response = requests.request(method, url, params=params)
+    response = requests.request(method, url, params=params, headers=headers)
     # pylint: enable=too-many-function-args
     # pylint: disable=no-member
     if response.status_code != requests.codes.ok:
diff --git a/quizler/utils.py b/quizler/utils.py
index bcb1edf..3495fc8 100644
--- a/quizler/utils.py
+++ b/quizler/utils.py
@@ -53,17 +53,17 @@ def print_common_terms(common_terms: List[Tuple[str, str, Set[str]]]):
                 print('    {}'.format(term))
 
 
-def delete_term(set_id, term_id, client_id):
+def delete_term(set_id, term_id, client_id, access_token):
     """Delete the given term."""
-    api_call('delete', 'sets/{}/terms/{}'.format(set_id, term_id), {}, client_id)
+    api_call('delete', 'sets/{}/terms/{}'.format(set_id, term_id), {}, client_id, access_token)
 
 
-def add_term(set_id, term: Term, client_id):
+def add_term(set_id, term: Term, client_id, access_token):
     """Add the given term to the given set."""
-    api_call('post', 'sets/{}/terms'.format(set_id), term.to_dict(), client_id)
+    api_call('post', 'sets/{}/terms'.format(set_id), term.to_dict(), client_id, access_token)
 
 
-def reset_term_stats(set_id, term_id, client_id, user_id):
+def reset_term_stats(set_id, term_id, client_id, user_id, access_token):
     """Reset the stats of a term by deleting and re-creating it."""
     found_sets = [user_set for user_set in get_user_sets(client_id, user_id)
                   if user_set.set_id == set_id]
@@ -81,9 +81,9 @@ def reset_term_stats(set_id, term_id, client_id, user_id):
         raise NotImplementedError('"{}" has an image and is thus not supported'.format(term))
 
     print('Deleting "{}"...'.format(term))
-    delete_term(set_id, term_id, client_id)
+    delete_term(set_id, term_id, client_id, access_token)
     print('Re-creating "{}"...'.format(term))
-    add_term(set_id, term_id, client_id)
+    add_term(set_id, term_id, client_id, access_token)
     print('Done')
 
 
diff --git a/tests/quizler/test_lib.py b/tests/quizler/test_lib.py
index 2f8868a..ddeb0f6 100644
--- a/tests/quizler/test_lib.py
+++ b/tests/quizler/test_lib.py
@@ -46,7 +46,8 @@ def test_correct_url_was_called(self, mock_request):
         mock_request.assert_called_once_with(
             'get',
             'https://api.quizlet.com/2.0/end_point',
-            params={'client_id': 'client_id'}
+            params={'client_id': 'client_id'},
+            headers=None
         )
 
     @mock.patch('requests.request')