diff --git a/permit/api/base.py b/permit/api/base.py
index 25b257e..4719327 100644
--- a/permit/api/base.py
+++ b/permit/api/base.py
@@ -174,7 +174,7 @@ def _build_http_client(self, endpoint_url: str = "", *, use_pdp: bool = False, *
             base_url=self.config.pdp if use_pdp else self.config.api_url,
             headers={
                 "Content-Type": "application/json",
-                "Authorization": f"bearer {self.config.token}",
+                "Authorization": f"Bearer {self.config.token}",
                 **optional_headers,
             },
         )
diff --git a/permit/enforcement/enforcer.py b/permit/enforcement/enforcer.py
index c72f93e..cf3df97 100644
--- a/permit/enforcement/enforcer.py
+++ b/permit/enforcement/enforcer.py
@@ -44,7 +44,7 @@ def __init__(self, config: PermitConfig):
         self._context_store = ContextStore()
         self._headers = {
             "Content-Type": "application/json",
-            "Authorization": f"bearer {self._config.token}",
+            "Authorization": f"Bearer {self._config.token}",
         }
         self._base_url = self._config.pdp
 
diff --git a/permit/pdp_api/base.py b/permit/pdp_api/base.py
index a82bd61..e34a5e5 100644
--- a/permit/pdp_api/base.py
+++ b/permit/pdp_api/base.py
@@ -48,7 +48,7 @@ def _build_http_client(self, endpoint_url: str = "", **kwargs):
             base_url=f"{self.config.pdp}",
             headers={
                 "Content-Type": "application/json",
-                "Authorization": f"bearer {self.config.token}",
+                "Authorization": f"Bearer {self.config.token}",
             },
         )
         client_config_dict = client_config.dict()
diff --git a/permit/pdp_api/pdp_api_client.py b/permit/pdp_api/pdp_api_client.py
index e0cf204..629e926 100644
--- a/permit/pdp_api/pdp_api_client.py
+++ b/permit/pdp_api/pdp_api_client.py
@@ -19,7 +19,7 @@ def __init__(self, config: PermitConfig):
         self._config = config
         self._headers = {
             "Content-Type": "application/json",
-            "Authorization": f"bearer {self._config.token}",
+            "Authorization": f"Bearer {self._config.token}",
         }
         self._base_url = self._config.pdp