diff --git a/lms/djangoapps/courseware/access.py b/lms/djangoapps/courseware/access.py
index 83b47e339c..da85f102dd 100644
--- a/lms/djangoapps/courseware/access.py
+++ b/lms/djangoapps/courseware/access.py
@@ -42,6 +42,7 @@ from lms.djangoapps.courseware.masquerade import get_masquerade_role, is_masquer
 from lms.djangoapps.ccx.custom_exception import CCXLocatorValidationException
 from lms.djangoapps.ccx.models import CustomCourseForEdX
 from lms.djangoapps.mobile_api.models import IgnoreMobileAvailableFlagConfig
+from lms.djangoapps.courseware.toggles import is_courses_default_invite_only_enabled
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
 from openedx.features.course_duration_limits.access import check_course_expired
 from common.djangoapps.student import auth
@@ -271,7 +272,8 @@ def _can_enroll_courselike(user, courselike):
     if _has_staff_access_to_descriptor(user, courselike, course_key):
         return ACCESS_GRANTED
 
-    if courselike.invitation_only:
+    # Access denied when default value of COURSES_INVITE_ONLY set to True
+    if is_courses_default_invite_only_enabled() or courselike.invitation_only:
         debug("Deny: invitation only")
         return ACCESS_DENIED
 
diff --git a/lms/djangoapps/courseware/tests/test_access.py b/lms/djangoapps/courseware/tests/test_access.py
index ac2773f6ef..c82723323f 100644
--- a/lms/djangoapps/courseware/tests/test_access.py
+++ b/lms/djangoapps/courseware/tests/test_access.py
@@ -14,6 +14,7 @@ from ccx_keys.locator import CCXLocator
 from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
 from django.test import TestCase
 from django.test.client import RequestFactory
+from django.test.utils import override_settings
 from django.urls import reverse
 from milestones.tests.utils import MilestonesTestCaseMixin
 from opaque_keys.edx.locator import CourseLocator
@@ -500,6 +501,48 @@ class AccessTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase, MilestonesTes
         )
         assert not access._has_access_course(user, 'enroll', course)
 
+    @override_settings(COURSES_INVITE_ONLY=False)
+    def test__course_default_invite_only_flag_false(self):
+        """
+        Ensure that COURSES_INVITE_ONLY does not take precedence,
+        if it is not set over the course invitation_only settings.
+        """
+
+        user = UserFactory.create()
+
+        # User cannot enroll in the course if it is just invitation only.
+        course = self._mock_course_with_invitation(invitation=True)
+        self.assertFalse(access._has_access_course(user, 'enroll', course))
+
+        # User can enroll in the course if it is not just invitation only.
+        course = self._mock_course_with_invitation(invitation=False)
+        self.assertTrue(access._has_access_course(user, 'enroll', course))
+
+    @override_settings(COURSES_INVITE_ONLY=True)
+    def test__course_default_invite_only_flag_true(self):
+        """
+        Ensure that COURSES_INVITE_ONLY takes precedence over the course invitation_only settings.
+        """
+
+        user = UserFactory.create()
+
+        # User cannot enroll in the course if it is just invitation only and COURSES_INVITE_ONLY is also set.
+        course = self._mock_course_with_invitation(invitation=True)
+        self.assertFalse(access._has_access_course(user, 'enroll', course))
+
+        # User cannot enroll in the course if COURSES_INVITE_ONLY is set despite of the course invitation_only value.
+        course = self._mock_course_with_invitation(invitation=False)
+        self.assertFalse(access._has_access_course(user, 'enroll', course))
+
+    def _mock_course_with_invitation(self, invitation):
+        yesterday = datetime.datetime.now(pytz.utc) - datetime.timedelta(days=1)
+        tomorrow = datetime.datetime.now(pytz.utc) + datetime.timedelta(days=1)
+        return Mock(
+            enrollment_start=yesterday, enrollment_end=tomorrow,
+            id=CourseLocator('edX', 'test', '2012_Fall'), enrollment_domain='',
+            invitation_only=invitation
+        )
+
     def test__user_passed_as_none(self):
         """Ensure has_access handles a user being passed as null"""
         access.has_access(None, 'staff', 'global', None)
diff --git a/lms/djangoapps/courseware/toggles.py b/lms/djangoapps/courseware/toggles.py
index 715d178804..ee3430da79 100644
--- a/lms/djangoapps/courseware/toggles.py
+++ b/lms/djangoapps/courseware/toggles.py
@@ -2,7 +2,7 @@
 Toggles for courseware in-course experience.
 """
 
-from edx_toggles.toggles import LegacyWaffleFlagNamespace
+from edx_toggles.toggles import LegacyWaffleFlagNamespace, SettingToggle
 from opaque_keys.edx.keys import CourseKey
 
 from openedx.core.djangoapps.waffle_utils import CourseWaffleFlag
@@ -190,3 +190,18 @@ def streak_celebration_is_active(course_key):
         courseware_mfe_progress_milestones_are_active(course_key) and
         COURSEWARE_MICROFRONTEND_PROGRESS_MILESTONES_STREAK_CELEBRATION.is_enabled(course_key)
     )
+
+
+# .. toggle_name: COURSES_INVITE_ONLY
+# .. toggle_implementation: SettingToggle
+# .. toggle_type: feature_flag
+# .. toggle_default: False
+# .. toggle_description: Setting this sets the default value of INVITE_ONLY across all courses in a given deployment
+# .. toggle_category: admin
+# .. toggle_use_cases: open_edx
+# .. toggle_creation_date: 2019-05-16
+# .. toggle_expiration_date: None
+# .. toggle_tickets: https://github.com/mitodl/edx-platform/issues/123
+# .. toggle_status: unsupported
+def is_courses_default_invite_only_enabled():
+    return SettingToggle("COURSES_INVITE_ONLY", default=False).is_enabled()
diff --git a/lms/djangoapps/courseware/views/views.py b/lms/djangoapps/courseware/views/views.py
index f15213d831..a62713f218 100644
--- a/lms/djangoapps/courseware/views/views.py
+++ b/lms/djangoapps/courseware/views/views.py
@@ -86,6 +86,8 @@ from lms.djangoapps.courseware.permissions import (  # lint-amnesty, pylint: dis
     VIEW_COURSEWARE,
     VIEW_XQA_INTERFACE
 )
+
+from lms.djangoapps.courseware.toggles import is_courses_default_invite_only_enabled
 from lms.djangoapps.courseware.user_state_client import DjangoXBlockUserStateClient
 from lms.djangoapps.experiments.utils import get_experiment_user_metadata_context
 from lms.djangoapps.grades.api import CourseGradeFactory
@@ -947,7 +949,7 @@ def course_about(request, course_id):
 
         # Used to provide context to message to student if enrollment not allowed
         can_enroll = bool(request.user.has_perm(ENROLL_IN_COURSE, course))
-        invitation_only = course.invitation_only
+        invitation_only = is_courses_default_invite_only_enabled() or course.invitation_only
         is_course_full = CourseEnrollment.objects.is_course_full(course)
 
         # Register button should be disabled if one of the following is true:
diff --git a/lms/templates/courseware/course_about.html b/lms/templates/courseware/course_about.html
index a65258c527..47c7f29755 100644
--- a/lms/templates/courseware/course_about.html
+++ b/lms/templates/courseware/course_about.html
@@ -5,6 +5,7 @@ from django.utils.translation import ugettext as _
 from django.utils.translation import pgettext
 from django.urls import reverse
 from lms.djangoapps.courseware.courses import get_course_about_section
+from lms.djangoapps.courseware.toggles import is_courses_default_invite_only_enabled
 from django.conf import settings
 from six import text_type
 from common.djangoapps.edxmako.shortcuts import marketing_link
@@ -90,7 +91,7 @@ from six import string_types
           <span class="register disabled">
             ${_("Course is full")}
           </span>
-        % elif invitation_only and not can_enroll:
+        % elif (is_courses_default_invite_only_enabled() or invitation_only) and not can_enroll:
           <span class="register disabled">${_("Enrollment in this course is by invitation only")}</span>
         ## Shib courses need the enrollment button to be displayed even when can_enroll is False,
         ## because AnonymousUsers cause can_enroll for shib courses to be False, but we need them to be able to click