diff --git a/lib/Github/Api/Organization.php b/lib/Github/Api/Organization.php
index 32eba7d2d87..46dd975ca0a 100644
--- a/lib/Github/Api/Organization.php
+++ b/lib/Github/Api/Organization.php
@@ -4,6 +4,7 @@
 
 use Github\Api\Organization\Hooks;
 use Github\Api\Organization\Members;
+use Github\Api\Organization\OutsideCollaborators;
 use Github\Api\Organization\Teams;
 
 /**
@@ -100,6 +101,14 @@ public function teams()
         return new Teams($this->client);
     }
 
+    /**
+     * @return OutsideCollaborators
+     */
+    public function outsideCollaborators()
+    {
+        return new OutsideCollaborators($this->client);
+    }
+
     /**
      * @link http://developer.github.com/v3/issues/#list-issues
      *
diff --git a/lib/Github/Api/Organization/OutsideCollaborators.php b/lib/Github/Api/Organization/OutsideCollaborators.php
new file mode 100644
index 00000000000..958100a56ee
--- /dev/null
+++ b/lib/Github/Api/Organization/OutsideCollaborators.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace Github\Api\Organization;
+
+use Github\Api\AbstractApi;
+
+/**
+ * @link   https://developer.github.com/v3/orgs/outside_collaborators/
+ *
+ * @author Matthieu Calie <matthieu@calie.be>
+ */
+class OutsideCollaborators extends AbstractApi
+{
+    /**
+     * @link https://developer.github.com/v3/orgs/outside_collaborators/#list-outside-collaborators-for-an-organization
+     *
+     * @param string $organization the organization
+     * @param array  $params
+     *
+     * @return array the organizations
+     */
+    public function all($organization, array $params = [])
+    {
+        return $this->get('/orgs/'.rawurlencode($organization).'/outside_collaborators', $params);
+    }
+
+    /**
+     * @link https://developer.github.com/v3/orgs/outside_collaborators/#convert-an-organization-member-to-outside-collaborator
+     *
+     * @param string $organization the organization
+     * @param string $username     the github username
+     *
+     * @return array
+     */
+    public function convert($organization, $username)
+    {
+        return $this->put('/orgs/'.rawurlencode($organization).'/outside_collaborators/'.rawurldecode($username));
+    }
+
+    /**
+     * @link https://developer.github.com/v3/orgs/outside_collaborators/#remove-outside-collaborator-from-an-organization
+     *
+     * @param string $organization the organization
+     * @param string $username     the username
+     *
+     * @return array
+     */
+    public function remove($organization, $username)
+    {
+        return $this->delete('/orgs/'.rawurlencode($organization).'/outside_collaborators/'.rawurldecode($username));
+    }
+}
diff --git a/lib/Github/Client.php b/lib/Github/Client.php
index 86ed95c19d8..a6170570032 100644
--- a/lib/Github/Client.php
+++ b/lib/Github/Client.php
@@ -19,49 +19,50 @@
 /**
  * Simple yet very cool PHP GitHub client.
  *
- * @method Api\CurrentUser currentUser()
- * @method Api\CurrentUser me()
- * @method Api\Enterprise ent()
- * @method Api\Enterprise enterprise()
- * @method Api\Miscellaneous\CodeOfConduct codeOfConduct()
- * @method Api\Miscellaneous\Emojis emojis()
- * @method Api\Miscellaneous\Licenses licenses()
- * @method Api\GitData git()
- * @method Api\GitData gitData()
- * @method Api\Gists gist()
- * @method Api\Gists gists()
- * @method Api\Miscellaneous\Gitignore gitignore()
- * @method Api\Integrations integration() (deprecated)
- * @method Api\Integrations integrations() (deprecated)
- * @method Api\Apps apps()
- * @method Api\Issue issue()
- * @method Api\Issue issues()
- * @method Api\Markdown markdown()
- * @method Api\Notification notification()
- * @method Api\Notification notifications()
- * @method Api\Organization organization()
- * @method Api\Organization organizations()
- * @method Api\Organization\Projects orgProject()
- * @method Api\Organization\Projects orgProjects()
- * @method Api\Organization\Projects organizationProject()
- * @method Api\Organization\Projects organizationProjects()
- * @method Api\PullRequest pr()
- * @method Api\PullRequest pullRequest()
- * @method Api\PullRequest pullRequests()
- * @method Api\RateLimit rateLimit()
- * @method Api\Repo repo()
- * @method Api\Repo repos()
- * @method Api\Repo repository()
- * @method Api\Repo repositories()
- * @method Api\Search search()
- * @method Api\Organization\Teams team()
- * @method Api\Organization\Teams teams()
- * @method Api\User user()
- * @method Api\User users()
- * @method Api\Authorizations authorization()
- * @method Api\Authorizations authorizations()
- * @method Api\Meta meta()
- * @method Api\GraphQL graphql()
+ * @method Api\CurrentUser                       currentUser()
+ * @method Api\CurrentUser                       me()
+ * @method Api\Enterprise                        ent()
+ * @method Api\Enterprise                        enterprise()
+ * @method Api\Miscellaneous\CodeOfConduct       codeOfConduct()
+ * @method Api\Miscellaneous\Emojis              emojis()
+ * @method Api\Miscellaneous\Licenses            licenses()
+ * @method Api\GitData                           git()
+ * @method Api\GitData                           gitData()
+ * @method Api\Gists                             gist()
+ * @method Api\Gists                             gists()
+ * @method Api\Miscellaneous\Gitignore           gitignore()
+ * @method Api\Integrations                      integration() (deprecated)
+ * @method Api\Integrations                      integrations() (deprecated)
+ * @method Api\Apps                              apps()
+ * @method Api\Issue                             issue()
+ * @method Api\Issue                             issues()
+ * @method Api\Markdown                          markdown()
+ * @method Api\Notification                      notification()
+ * @method Api\Notification                      notifications()
+ * @method Api\Organization                      organization()
+ * @method Api\Organization                      organizations()
+ * @method Api\Organization\Projects             orgProject()
+ * @method Api\Organization\Projects             orgProjects()
+ * @method Api\Organization\Projects             organizationProject()
+ * @method Api\Organization\Projects             organizationProjects()
+ * @method Api\Organization\OutsideCollaborators outsideCollaborators()
+ * @method Api\PullRequest                       pr()
+ * @method Api\PullRequest                       pullRequest()
+ * @method Api\PullRequest                       pullRequests()
+ * @method Api\RateLimit                         rateLimit()
+ * @method Api\Repo                              repo()
+ * @method Api\Repo                              repos()
+ * @method Api\Repo                              repository()
+ * @method Api\Repo                              repositories()
+ * @method Api\Search                            search()
+ * @method Api\Organization\Teams                team()
+ * @method Api\Organization\Teams                teams()
+ * @method Api\User                              user()
+ * @method Api\User                              users()
+ * @method Api\Authorizations                    authorization()
+ * @method Api\Authorizations                    authorizations()
+ * @method Api\Meta                              meta()
+ * @method Api\GraphQL                           graphql()
  *
  * @author Joseph Bielawski <stloyd@gmail.com>
  *
@@ -318,6 +319,11 @@ public function api($name)
                 $api = new Api\GraphQL($this);
                 break;
 
+            case 'outsideCollaborators':
+            case 'outside_collaborators':
+                $api = new Api\Organization\OutsideCollaborators($this);
+                break;
+
             default:
                 throw new InvalidArgumentException(sprintf('Undefined api instance called: "%s"', $name));
         }
diff --git a/test/Github/Tests/Api/Organization/OutsideCollaboratorsTest.php b/test/Github/Tests/Api/Organization/OutsideCollaboratorsTest.php
new file mode 100644
index 00000000000..eb74b266c09
--- /dev/null
+++ b/test/Github/Tests/Api/Organization/OutsideCollaboratorsTest.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Github\Tests\Api\Organization;
+
+use Github\Tests\Api\TestCase;
+
+class OutsideCollaboratorsTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function shouldGetAllRepositoryProjects()
+    {
+        $expectedValue = [['login' => 'KnpLabs']];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/orgs/KnpLabs/outside_collaborators')
+            ->will($this->returnValue($expectedValue));
+
+        $this->assertEquals($expectedValue, $api->all('KnpLabs'));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldConvertAnOrganizationMemberToOutsideCollaborator()
+    {
+        $expectedValue = 'expectedResponse';
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('put')
+            ->with('/orgs/KnpLabs/outside_collaborators/username')
+            ->will($this->returnValue($expectedValue));
+
+        $this->assertEquals($expectedValue, $api->convert('KnpLabs', 'username'));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldRemoveAnOutsideCollaboratorFromAnOrganization()
+    {
+        $expectedValue = 'expectedResponse';
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('delete')
+            ->with('/orgs/KnpLabs/outside_collaborators/username')
+            ->will($this->returnValue($expectedValue));
+
+        $this->assertEquals($expectedValue, $api->remove('KnpLabs', 'username'));
+    }
+
+    /**
+     * @return string
+     */
+    protected function getApiClass()
+    {
+        return \Github\Api\Organization\OutsideCollaborators::class;
+    }
+}
diff --git a/test/Github/Tests/ClientTest.php b/test/Github/Tests/ClientTest.php
index 550bc8169f6..25b559329da 100644
--- a/test/Github/Tests/ClientTest.php
+++ b/test/Github/Tests/ClientTest.php
@@ -209,6 +209,9 @@ public function getApiClassesProvider()
             ['authorizations', Api\Authorizations::class],
 
             ['meta', Api\Meta::class],
+
+            ['outsideCollaborators', Api\Organization\OutsideCollaborators::class],
+            ['outside_collaborators', Api\Organization\OutsideCollaborators::class],
         ];
     }