diff --git a/github/AuthenticatedUser.py b/github/AuthenticatedUser.py
index ad1523c4..760a264e 100644
--- a/github/AuthenticatedUser.py
+++ b/github/AuthenticatedUser.py
@@ -1051,6 +1051,24 @@ class AuthenticatedUser(github.GithubObject.CompletableGithubObject):
             "/user/watched/" + watched._identity
         )
 
+    def accept_invitation(self, invitation):
+        """
+        :calls: `PATCH /user/repository_invitations/:invitation_id <https://developer.github.com/v3/repos/invitations/>`
+        :param invitation: :class:`github.Invitation.Invitation` or int
+        :rtype: None
+        """
+        assert isinstance(invitation, github.Invitation.Invitation) or isinstance(invitation, int)
+
+        if isinstance(invitation, github.Invitation.Invitation):
+            invitation = invitation.id
+
+        headers, data = self._requester.requestJsonAndCheck(
+            "PATCH",
+            "/user/repository_invitations/" + str(invitation),
+            headers={'Accept': 'application/vnd.github.swamp-thing-preview+json'},
+            input={}
+        )
+
     def _initAttributes(self):
         self._avatar_url = github.GithubObject.NotSet
         self._bio = github.GithubObject.NotSet
diff --git a/github/Invitation.py b/github/Invitation.py
new file mode 100644
index 00000000..bf2668cc
--- /dev/null
+++ b/github/Invitation.py
@@ -0,0 +1,109 @@
+# -*- coding: utf-8 -*-
+
+# ########################## Copyrights and license ############################
+#                                                                              #
+# Copyright 2017 Jannis Gebauer <ja.geb@me.com>                                #
+#                                                                              #
+# This file is part of PyGithub.                                               #
+# http://pygithub.github.io/PyGithub/v1/index.html                             #
+#                                                                              #
+# PyGithub is free software: you can redistribute it and/or modify it under    #
+# the terms of the GNU Lesser General Public License as published by the Free  #
+# Software Foundation, either version 3 of the License, or (at your option)    #
+# any later version.                                                           #
+#                                                                              #
+# PyGithub is distributed in the hope that it will be useful, but WITHOUT ANY  #
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS    #
+# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more #
+# details.                                                                     #
+#                                                                              #
+# You should have received a copy of the GNU Lesser General Public License     #
+# along with PyGithub. If not, see <http://www.gnu.org/licenses/>.             #
+#                                                                              #
+# ##############################################################################
+
+import urllib
+
+import github.GithubObject
+
+
+class Invitation(github.GithubObject.CompletableGithubObject):
+    """
+    This class represents repository invitations. The reference can be found here https://developer.github.com/v3/repos/invitations/
+    """
+
+    def __repr__(self):
+        return self.get__repr__({"id": self._id.value})
+
+    @property
+    def id(self):
+        """
+        :type: integer
+        """
+        self._completeIfNotSet(self._id)
+        return self._id.value
+
+    @property
+    def permissions(self):
+        """
+        :type: string
+        """
+        self._completeIfNotSet(self._permissions)
+        return self._permissions.value
+
+    @property
+    def created_at(self):
+        """
+        :type: string
+        """
+        self._completeIfNotSet(self._created_at)
+        return self._created_at.value
+
+    @property
+    def url(self):
+        """
+        :type: string
+        """
+        self._completeIfNotSet(self._url)
+        return self._url.value
+
+
+    @property
+    def html_url(self):
+        """
+        :type: string
+        """
+        self._completeIfNotSet(self._html_url)
+        return self._html_url.value
+
+    @property
+    def repository(self):
+        """
+        :type: Repository
+        """
+        self._completeIfNotSet(self._repository)
+        return self._repository.value
+
+    def _initAttributes(self):
+        self._id = github.GithubObject.NotSet
+        self._permissions = github.GithubObject.NotSet
+        self._created_at = github.GithubObject.NotSet
+        self._url = github.GithubObject.NotSet
+        self._html_url = github.GithubObject.NotSet
+        self._repository = github.GithubObject.NotSet
+
+    def _useAttributes(self, attributes):
+        if "repository" in attributes:  # pragma no branch
+            self._assignee = self._makeClassAttribute(github.Repository.Repository, attributes["repository"])
+        if "created_at" in attributes:  # pragma no branch
+            self._closed_at = self._makeDatetimeAttribute(attributes["created_at"])
+        if "id" in attributes:  # pragma no branch
+            self._id = self._makeIntAttribute(attributes["id"])
+
+        if "permissions" in attributes:  # pragma no branch
+            self._permissions = self._makeStringAttribute(attributes["permissions"])
+        if "url" in attributes:  # pragma no branch
+            self._url = self._makeStringAttribute(attributes["url"])
+        if "html_url" in attributes:  # pragma no branch
+            self._html_url = self._makeStringAttribute(attributes["html_url"])
+
diff --git a/github/MainClass.py b/github/MainClass.py
index 2184547e..024f0a46 100644
--- a/github/MainClass.py
+++ b/github/MainClass.py
@@ -50,6 +50,7 @@ import StatusMessage
 import RateLimit
 import InstallationAuthorization
 import GithubException
+import Invitation
 
 atLeastPython3 = sys.hexversion >= 0x03000000
 
diff --git a/github/Repository.py b/github/Repository.py
index b079bc88..5ae3d975 100644
--- a/github/Repository.py
+++ b/github/Repository.py
@@ -673,8 +673,13 @@ class Repository(github.GithubObject.CompletableGithubObject):
 
         headers, data = self._requester.requestJsonAndCheck(
             "PUT",
-            self.url + "/collaborators/" + collaborator
+            self.url + "/collaborators/" + collaborator,
+            headers={'Accept': 'application/vnd.github.swamp-thing-preview+json'}
         )
+        # return an invitation object if there's data returned by the API. If data is empty
+        # there's a pending invitation for the given user.
+        return github.Invitation.Invitation(self._requester, headers, data, completed=True) if \
+            data is not None else None
 
     def compare(self, base, head):
         """
diff --git a/github/tests/AuthenticatedUser.py b/github/tests/AuthenticatedUser.py
index 57dd1d59..bb00ccc7 100644
--- a/github/tests/AuthenticatedUser.py
+++ b/github/tests/AuthenticatedUser.py
@@ -234,3 +234,6 @@ class AuthenticatedUser(Framework.TestCase):
 
     def testGetTeams(self):
         self.assertListKeyEqual(self.user.get_teams(), lambda t: t.name, ["Owners", "Honoraries", "Honoraries", "Honoraries", "Honoraries", "Honoraries", "Honoraries", "Honoraries", "Honoraries", "Honoraries"])
+
+    def testAcceptInvitation(self):
+        self.assertIsNone(self.user.accept_invitation(4294886))
\ No newline at end of file
diff --git a/github/tests/ReplayData/AuthenticatedUser.testAcceptInvitation.txt b/github/tests/ReplayData/AuthenticatedUser.testAcceptInvitation.txt
new file mode 100644
index 00000000..e6f4a1f3
--- /dev/null
+++ b/github/tests/ReplayData/AuthenticatedUser.testAcceptInvitation.txt
@@ -0,0 +1,11 @@
+https
+PATCH
+api.github.com
+None
+/user/repository_invitations/4294886
+{'Content-Type': 'application/json', 'Authorization': 'Basic login_and_password_removed', 'Accept': 'application/vnd.github.swamp-thing-preview+json', 'User-Agent': 'PyGithub/Python'}
+{}
+204
+[('status', '204 No Content'), ('x-ratelimit-remaining', '4981'), ('x-github-media-type', 'github.swamp-thing-preview; format=json'), ('x-content-type-options', 'nosniff'), ('content-security-policy', "default-src 'none'"), ('access-control-expose-headers', 'ETag, Link, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval'), ('x-github-request-id', 'D039:11DAA:17FC875:24A1090:59635F0C'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('vary', 'Accept-Encoding'), ('server', 'GitHub.com'), ('x-ratelimit-limit', '5000'), ('x-runtime-rack', '0.072659'), ('x-xss-protection', '1; mode=block'), ('x-served-by', '7f48e2f7761567e923121f17538d7a6d'), ('date', 'Mon, 10 Jul 2017 11:03:40 GMT'), ('access-control-allow-origin', '*'), ('x-frame-options', 'deny'), ('x-ratelimit-reset', '1499685825')]
+
+
diff --git a/github/tests/ReplayData/Issue214.testCollaborators.txt b/github/tests/ReplayData/Issue214.testCollaborators.txt
index 5880b26a..26219ad2 100644
--- a/github/tests/ReplayData/Issue214.testCollaborators.txt
+++ b/github/tests/ReplayData/Issue214.testCollaborators.txt
@@ -36,7 +36,7 @@ PUT
 api.github.com
 None
 /repos/farrd/PyGithub/collaborators/marcmenges
-{'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
+{'Accept': 'application/vnd.github.swamp-thing-preview+json', 'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
 null
 204
 [('status', '204 No Content'), ('x-ratelimit-remaining', '4762'), ('x-github-media-type', 'github.beta; format=json'), ('x-content-type-options', 'nosniff'), ('access-control-expose-headers', 'ETag, Link, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval'), ('x-github-request-id', 'A99159CE:6DAA:6192A15:52AF94DC'), ('vary', 'Accept-Encoding'), ('server', 'GitHub.com'), ('x-ratelimit-limit', '5000'), ('access-control-allow-credentials', 'true'), ('date', 'Tue, 17 Dec 2013 00:03:41 GMT'), ('access-control-allow-origin', '*'), ('x-ratelimit-reset', '1387240227')]
diff --git a/github/tests/ReplayData/Repository.testAssignees.txt b/github/tests/ReplayData/Repository.testAssignees.txt
index cf02ca6a..d7138afd 100644
--- a/github/tests/ReplayData/Repository.testAssignees.txt
+++ b/github/tests/ReplayData/Repository.testAssignees.txt
@@ -47,7 +47,7 @@ PUT
 api.github.com
 None
 /repos/jacquev6/PyGithub/collaborators/Lyloa
-{'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
+{'Accept': 'application/vnd.github.swamp-thing-preview+json', 'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
 null
 204
 [('status', '204 No Content'), ('x-ratelimit-remaining', '4993'), ('x-github-media-type', 'github.beta; format=json'), ('x-content-type-options', 'nosniff'), ('server', 'nginx/1.0.13'), ('connection', 'keep-alive'), ('x-ratelimit-limit', '5000'), ('cache-control', ''), ('date', 'Fri, 07 Sep 2012 23:12:27 GMT')]
diff --git a/github/tests/ReplayData/Repository.testCollaborators.txt b/github/tests/ReplayData/Repository.testCollaborators.txt
index 393599f2..1465123f 100644
--- a/github/tests/ReplayData/Repository.testCollaborators.txt
+++ b/github/tests/ReplayData/Repository.testCollaborators.txt
@@ -25,7 +25,7 @@ PUT
 api.github.com
 None
 /repos/jacquev6/PyGithub/collaborators/Lyloa
-{'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
+{'Accept': 'application/vnd.github.swamp-thing-preview+json', 'Authorization': 'Basic login_and_password_removed', 'User-Agent': 'PyGithub/Python'}
 null
 204
 [('status', '204 No Content'), ('x-ratelimit-remaining', '4953'), ('server', 'nginx/1.0.13'), ('connection', 'keep-alive'), ('x-ratelimit-limit', '5000'), ('etag', '"d41d8cd98f00b204e9800998ecf8427e"'), ('date', 'Sun, 27 May 2012 05:34:27 GMT')]