diff --git a/office365/runtime/auth/authentication_context.py b/office365/runtime/auth/authentication_context.py
index aa373045..f0222593 100644
--- a/office365/runtime/auth/authentication_context.py
+++ b/office365/runtime/auth/authentication_context.py
@@ -184,8 +184,9 @@ def with_credentials(self, credentials, **kwargs):
                 provider = NtlmProvider(credentials.userName, credentials.password)
             else:
                 browser_mode = kwargs.get("browser_mode", False)
+                environment = kwargs.get("environment")
                 provider = SamlTokenProvider(
-                    self.url, credentials.userName, credentials.password, browser_mode
+                    self.url, credentials.userName, credentials.password, browser_mode, environment
                 )
         else:
             raise ValueError("Unknown credential type")
diff --git a/office365/runtime/auth/providers/saml_token_provider.py b/office365/runtime/auth/providers/saml_token_provider.py
index 503e4035..5a28c1d9 100644
--- a/office365/runtime/auth/providers/saml_token_provider.py
+++ b/office365/runtime/auth/providers/saml_token_provider.py
@@ -40,7 +40,7 @@ def is_valid_auth_cookies(values):
 
 
 class SamlTokenProvider(AuthenticationProvider, office365.logger.LoggerContext):
-    def __init__(self, url, username, password, browser_mode):
+    def __init__(self, url, username, password, browser_mode, environment='commercial'):
         """
         SAML Security Token Service provider (claims-based authentication)
 
@@ -48,11 +48,14 @@ def __init__(self, url, username, password, browser_mode):
         :param str username: Typically a UPN in the form of an email address
         :param str password: The password
         :param bool browser_mode:
+        :param str environment: The Office 365 Cloud Environment endpoint used for authentication.
+        By default, this will be set to commercial ('commercial', 'GCCH')
         """
         # Security Token Service info
-        self._sts_profile = STSProfile(resolve_base_url(url))
+        self._sts_profile = STSProfile(resolve_base_url(url), environment)
         # Obtain authentication cookies, using the browser mode
         self._browser_mode = browser_mode
+        self._environment = environment
         # Last occurred error
         self.error = ""
         self._username = username
diff --git a/office365/runtime/auth/sts_profile.py b/office365/runtime/auth/sts_profile.py
index b29c0877..6ce8ed3d 100644
--- a/office365/runtime/auth/sts_profile.py
+++ b/office365/runtime/auth/sts_profile.py
@@ -4,13 +4,16 @@
 
 
 class STSProfile(object):
-    def __init__(self, authority_url):
+    def __init__(self, authority_url, environment):
         """
 
         :type authority_url: str
         """
         self.authorityUrl = authority_url
-        self.serviceUrl = "https://login.microsoftonline.com"
+        if environment == "GCCH":
+            self.serviceUrl = "https://login.microsoftonline.us"
+        else:
+            self.serviceUrl = "https://login.microsoftonline.com"
         self.securityTokenServicePath = "extSTS.srf"
         self.userRealmServicePath = "GetUserRealm.srf"
         self.tokenIssuer = "urn:federation:MicrosoftOnline"
diff --git a/office365/sharepoint/client_context.py b/office365/sharepoint/client_context.py
index 35ee766f..b3debb22 100644
--- a/office365/sharepoint/client_context.py
+++ b/office365/sharepoint/client_context.py
@@ -137,20 +137,23 @@ def with_access_token(self, token_func):
         return self
 
     def with_user_credentials(
-        self, username, password, allow_ntlm=False, browser_mode=False
+        self, username, password, allow_ntlm=False, browser_mode=False, environment='commercial'
     ):
-        # type: (str, str, bool, bool) -> Self
+        # type: (str, str, bool, bool, str) -> Self
         """
         Initializes a client to acquire a token via user credentials.
         :param str username: Typically, a UPN in the form of an email address
         :param str password: The password
         :param bool allow_ntlm: Flag indicates whether NTLM scheme is enabled. Disabled by default
         :param bool browser_mode:
+        :param str environment: The Office 365 Cloud Environment endpoint used for authentication.
+        By default, this will be set to commercial ('commercial', 'GCCH')
         """
         self.authentication_context.with_credentials(
             UserCredential(username, password),
             allow_ntlm=allow_ntlm,
             browser_mode=browser_mode,
+            environment=environment
         )
         return self