diff --git a/lms/djangoapps/course_api/blocks/tests/test_views.py b/lms/djangoapps/course_api/blocks/tests/test_views.py
index ccdf3a0c9c..f3667a20e2 100644
--- a/lms/djangoapps/course_api/blocks/tests/test_views.py
+++ b/lms/djangoapps/course_api/blocks/tests/test_views.py
@@ -11,6 +11,7 @@ from urllib.parse import urlencode, urlunparse
 from django.conf import settings
 from django.urls import reverse
 from opaque_keys.edx.locator import CourseLocator
+from completion.test_utils import CompletionWaffleTestMixin, submit_completions_for_testing
 
 from common.djangoapps.student.models import CourseEnrollment
 from common.djangoapps.student.tests.factories import AdminFactory, CourseEnrollmentFactory, UserFactory
@@ -395,7 +396,7 @@ class TestBlocksView(SharedModuleStoreTestCase):
         self.verify_response_with_requested_fields(response)
 
 
-class TestBlocksInCourseView(TestBlocksView):  # pylint: disable=test-inherits-tests
+class TestBlocksInCourseView(TestBlocksView, CompletionWaffleTestMixin):  # pylint: disable=test-inherits-tests
     """
     Test class for BlocksInCourseView
     """
@@ -404,6 +405,13 @@ class TestBlocksInCourseView(TestBlocksView):  # pylint: disable=test-inherits-t
         super(TestBlocksInCourseView, self).setUp()
         self.url = reverse('blocks_in_course')
         self.query_params['course_id'] = str(self.course_key)
+        self.override_waffle_switch(True)
+        self.non_orphaned_raw_block_usage_keys = set(
+            item.location
+            for item in self.store.get_items(self.course_key)
+            # remove all orphaned items in the course, except for the root 'course' block
+            if self.store.get_parent_location(item.location) or item.category == 'course'
+        )
 
     def test_no_course_id(self):
         self.query_params.pop('course_id')
@@ -419,3 +427,42 @@ class TestBlocksInCourseView(TestBlocksView):  # pylint: disable=test-inherits-t
         self.client.logout()
         self.query_params['username'] = ''
         self.verify_response(403, params={'course_id': str(CourseLocator('non', 'existent', 'course'))})
+
+    def test_completion_one_unit(self):
+        for item in self.store.get_items(self.course_key):
+            if item.category == 'html':
+                block_usage_key = item.location
+                break
+
+        submit_completions_for_testing(self.user, [block_usage_key])
+        response = self.verify_response(params={
+            'depth': 'all',
+            'requested_fields': ['completion', 'children'],
+        })
+
+        completion = response.data['blocks'][str(block_usage_key)].get('completion')
+        self.assertTrue(completion)
+
+    def test_completion_all_course(self):
+        for block in self.non_orphaned_raw_block_usage_keys:
+            submit_completions_for_testing(self.user, [block])
+
+        response = self.verify_response(params={
+            'depth': 'all',
+            'requested_fields': ['completion', 'children'],
+        })
+        for block_id in self.non_orphaned_block_usage_keys:
+            self.assertTrue(response.data['blocks'][block_id].get('completion'))
+
+    def test_completion_all_course_with_list_return_type(self):
+        for block in self.non_orphaned_raw_block_usage_keys:
+            submit_completions_for_testing(self.user, [block])
+
+        response = self.verify_response(params={
+            'depth': 'all',
+            'return_type': 'list',
+            'requested_fields': ['completion', 'children'],
+        })
+        for block in response.data:
+            if block['block_id'] in self.non_orphaned_block_usage_keys:
+                self.assertTrue(block.get('completion'))
diff --git a/lms/djangoapps/course_api/blocks/views.py b/lms/djangoapps/course_api/blocks/views.py
index 6f2421fcde..34e054a2e9 100644
--- a/lms/djangoapps/course_api/blocks/views.py
+++ b/lms/djangoapps/course_api/blocks/views.py
@@ -302,4 +302,54 @@ class BlocksInCourseView(BlocksView):
             course_usage_key = modulestore().make_course_usage_key(course_key)
         except InvalidKeyError:
             raise ValidationError(u"'{}' is not a valid course key.".format(six.text_type(course_key_string)))
-        return super(BlocksInCourseView, self).list(request, course_usage_key, hide_access_denials=hide_access_denials)
+        response = super().list(request, course_usage_key,
+                                hide_access_denials=hide_access_denials)
+
+        if 'completion' not in request.query_params.getlist('requested_fields', ''):
+            return response
+
+        course_blocks = {}
+        root = None
+        if request.query_params.get('return_type') == 'list':
+            for course_block in response.data:
+                course_blocks[course_block['id']] = course_block
+
+                if course_block.get('type') == 'course':
+                    root = course_block['id']
+        else:
+            root = response.data['root']
+            course_blocks = response.data['blocks']
+
+        if not root:
+            raise ValueError("Unable to find course block in {}".format(course_key_string))
+
+        recurse_mark_complete(root, course_blocks)
+        return response
+
+
+def recurse_mark_complete(block_id, blocks):
+    """
+    Helper function to walk course tree dict,
+    marking completion as 1 or 0
+
+    If all blocks are complete, mark parent block complete
+
+    :param blocks: dict of all blocks
+    :param block_id: root or child block id
+
+    :return:
+        block: course_outline_root_block block object or child block
+    """
+    block = blocks.get(block_id, {})
+    if block.get('completion') == 1:
+        return
+
+    child_blocks = block.get('children', block.get('descendents'))
+    # Unit blocks(blocks with no children) completion is being marked by patch call to completion service.
+    if child_blocks:
+        for child_block in child_blocks:
+            recurse_mark_complete(child_block, blocks)
+
+        completable_blocks = [blocks[child_block_id] for child_block_id in child_blocks
+                              if blocks[child_block_id].get('type') != 'discussion']
+        block['completion'] = int(all(child.get('completion') == 1 for child in completable_blocks))