diff --git a/gapi/apis/base_api.py b/gapi/apis/base_api.py
index 5f66e55..91e988f 100644
--- a/gapi/apis/base_api.py
+++ b/gapi/apis/base_api.py
@@ -1,19 +1,14 @@
 import datetime
-from googleapiclient.discovery import build
-
-from oauth2client import client
-from oauth2client import tools
-from oauth2client.file import Storage
-
-
-import httplib2
 import os
+import pickle
 
-import argparse
+
+from googleapiclient.discovery import build
+from google_auth_oauthlib.flow import InstalledAppFlow
+from google.auth.transport.requests import Request
 
 import gapi
 
-flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()
 
 HOUR = datetime.timedelta(seconds=60 ** 2)
 
@@ -38,29 +33,33 @@ class API:
         self.version = version
 
     def get_credentials(self):
-
-        credential_path = os.path.join(self.credentials_dir, "token.json")
-
-        store = Storage(credential_path)
-        credentials = store.get()
-        if not credentials or credentials.invalid:
-            flow = client.flow_from_clientsecrets(self.client_secret_file, self.scopes)
-            flow.user_agent = self.app_name
-            if flags:
-                credentials = tools.run_flow(flow, store, flags)
+        creds = None
+        # The file token.pickle stores the user's access and refresh tokens, and is
+        # created automatically when the authorization flow completes for the first
+        # time.
+        credential_path = os.path.join(self.credentials_dir, "token.pickle")
+        if os.path.exists(credential_path):
+            with open(credential_path, "rb") as token:
+                creds = pickle.load(token)
+        # If there are no (valid) credentials available, let the user log in.
+        if not creds or not creds.valid:
+            if creds and creds.expired and creds.refresh_token:
+                creds.refresh(Request())
             else:
-                credentials = tools.run(flow, store)
+                flow = InstalledAppFlow.from_client_secrets_file(
+                    self.client_secret_file, self.scopes
+                )
+                creds = flow.run_local_server(port=0)
+            # Save the credentials for the next run
             print("Storing credentials to " + credential_path)
-        return credentials
+            with open(credential_path, "wb") as token:
+                pickle.dump(creds, token)
+        return creds
 
     def build_service(self):
         credentials = self.get_credentials()
 
-        http = credentials.authorize(httplib2.Http())
-
-        service = build(
-            self.service_name, self.version, http=http, cache_discovery=False
-        )
+        service = build(self.service_name, self.version, credentials=credentials)
         return service
 
     def _needs_renewal(self):
diff --git a/requirements.txt b/requirements.txt
index 6bceffc..722d98f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,6 @@
+appdirs
 google-api-python-client
+google-auth-httplib2
+google-auth-oauthlib
 python-dateutil
-oauth2client
 tzlocal
-appdirs