diff --git a/httpx_auth/_oauth2/client_credentials.py b/httpx_auth/_oauth2/client_credentials.py
index ea46520..de7c5d5 100644
--- a/httpx_auth/_oauth2/client_credentials.py
+++ b/httpx_auth/_oauth2/client_credentials.py
@@ -3,6 +3,8 @@
 from typing import Union, Iterable
 
 import httpx
+import urllib.parse
+
 from httpx_auth._authentication import SupportMultiAuth
 from httpx_auth._oauth2.common import (
     OAuth2BaseAuth,
@@ -97,7 +99,10 @@ def request_new_token(self) -> tuple:
         return (self.state, token, expires_in) if expires_in else (self.state, token)
 
     def _configure_client(self, client: httpx.Client):
-        client.auth = (self.client_id, self.client_secret)
+        encoded_client = urllib.parse.quote(self.client_id, safe="")
+        encoded_secret = urllib.parse.quote(self.client_secret, safe="")
+
+        client.auth = (encoded_client, encoded_secret)
         client.timeout = self.timeout