diff --git a/app/controllers/discussion_topics_controller.rb b/app/controllers/discussion_topics_controller.rb
index 3e171265aa8..99005f0f3e7 100644
--- a/app/controllers/discussion_topics_controller.rb
+++ b/app/controllers/discussion_topics_controller.rb
@@ -533,6 +533,7 @@ class DiscussionTopicsController < ApplicationController
       URL_ROOT: named_context_url(@context, :api_v1_context_discussion_topics_url),
       PERMISSIONS: {
         CAN_CREATE_ASSIGNMENT: @context.respond_to?(:assignments) && @context.assignments.temp_record.grants_right?(@current_user, session, :create),
+        CAN_UPDATE_ASSIGNMENT: @context.respond_to?(:assignments) && @context.assignments.temp_record.grants_right?(@current_user, session, :update),
         CAN_ATTACH: @topic.grants_right?(@current_user, session, :attach),
         CAN_MODERATE: user_can_moderate,
         CAN_SET_GROUP: can_set_group_category,
diff --git a/spec/coffeescripts/views/DiscussionTopics/EditViewSpec.js b/spec/coffeescripts/views/DiscussionTopics/EditViewSpec.js
index 5597117f220..75f46d1ff36 100644
--- a/spec/coffeescripts/views/DiscussionTopics/EditViewSpec.js
+++ b/spec/coffeescripts/views/DiscussionTopics/EditViewSpec.js
@@ -255,6 +255,15 @@ test('does not show todo date elements when grading is enabled', function () {
   equal(view.$el.find('#todo_options')[0].style.display, 'none')
 })
 
+test('does retain the assignment when user with assignment-edit permission edits discussion', function () {
+  const view = this.editView({
+    withAssignment: true,
+    permissions: {CAN_UPDATE_ASSIGNMENT: true, CAN_CREATE_ASSIGNMENT: false},
+  })
+  const formData = view.getFormData()
+  equal(formData.set_assignment, '1')
+})
+
 test('does save todo date if allow_todo_date is checked and discussion is not graded', function () {
   ENV.STUDENT_PLANNER_ENABLED = true
   const todo_date = new Date('2017-05-25T08:00:00-0800')
diff --git a/ui/features/discussion_topic_edit/backbone/views/EditView.js b/ui/features/discussion_topic_edit/backbone/views/EditView.js
index 0d43c1ee5aa..500db499579 100644
--- a/ui/features/discussion_topic_edit/backbone/views/EditView.js
+++ b/ui/features/discussion_topic_edit/backbone/views/EditView.js
@@ -557,7 +557,14 @@ EditView.prototype.getFormData = function () {
     // The controller checks for set_assignment on the assignment model,
     // so we can't make it undefined here for the case of discussion topics.
     data.assignment = this.model.createAssignment({
-      set_assignment: '0',
+      // there are no assignment params here, so sending a '0' will cause the
+      // @discussion_topic.assignment to be removed in the back end if it already
+      // exists. By sending a '1', you can preserve the assignment as-is.
+      set_assignment: this.permissions.CAN_CREATE_ASSIGNMENT
+        ? '0'
+        : this.permissions.CAN_UPDATE_ASSIGNMENT
+        ? '1'
+        : '0',
     })
   }
   // these options get passed to Backbone.sync in ValidatedFormView