diff --git a/flytekit/clients/auth/token_client.py b/flytekit/clients/auth/token_client.py
index e7e55f74a9..7cbb42a13e 100644
--- a/flytekit/clients/auth/token_client.py
+++ b/flytekit/clients/auth/token_client.py
@@ -3,6 +3,7 @@
 import logging
 import time
 import typing
+import urllib.parse
 from dataclasses import dataclass
 from datetime import datetime, timedelta
 
@@ -57,14 +58,16 @@ def from_json_response(cls, j: typing.Dict) -> "DeviceCodeResponse":
 def get_basic_authorization_header(client_id: str, client_secret: str) -> str:
     """
     This function transforms the client id and the client secret into a header that conforms with http basic auth.
-    It joins the id and the secret with a : then base64 encodes it, then adds the appropriate text
+    It joins the id and the secret with a : then base64 encodes it, then adds the appropriate text. Secrets are
+    first URL encoded to escape illegal characters.
 
     :param client_id: str
     :param client_secret: str
     :rtype: str
     """
-    concated = "{}:{}".format(client_id, client_secret)
-    return "Basic {}".format(base64.b64encode(concated.encode(utf_8)).decode(utf_8))
+    encoded = urllib.parse.quote_plus(client_secret)
+    concatenated = "{}:{}".format(client_id, encoded)
+    return "Basic {}".format(base64.b64encode(concatenated.encode(utf_8)).decode(utf_8))
 
 
 def get_token(
diff --git a/tests/flytekit/unit/clients/auth/test_token_client.py b/tests/flytekit/unit/clients/auth/test_token_client.py
index 6e56c351bc..c22284cd38 100644
--- a/tests/flytekit/unit/clients/auth/test_token_client.py
+++ b/tests/flytekit/unit/clients/auth/test_token_client.py
@@ -18,6 +18,9 @@ def test_get_basic_authorization_header():
     header = get_basic_authorization_header("client_id", "abc")
     assert header == "Basic Y2xpZW50X2lkOmFiYw=="
 
+    header = get_basic_authorization_header("client_id", "abc%%$?\\/\\/")
+    assert header == "Basic Y2xpZW50X2lkOmFiYyUyNSUyNSUyNCUzRiU1QyUyRiU1QyUyRg=="
+
 
 @patch("flytekit.clients.auth.token_client.requests")
 def test_get_token(mock_requests):