diff --git a/app/assets/javascripts/sidebar/components/reviewers/sidebar_reviewers.vue b/app/assets/javascripts/sidebar/components/reviewers/sidebar_reviewers.vue
index 09ae9a38cdfe28990b145b53281d3b62d87b8682..aeeb2654836b05c9c7ae0f597ccc612ae9f78d1d 100644
--- a/app/assets/javascripts/sidebar/components/reviewers/sidebar_reviewers.vue
+++ b/app/assets/javascripts/sidebar/components/reviewers/sidebar_reviewers.vue
@@ -7,6 +7,7 @@ import { GlButton } from '@gitlab/ui';
 import { createAlert } from '~/alert';
 import { TYPE_ISSUE } from '~/issues/constants';
 import { __ } from '~/locale';
+import { InternalEvents } from '~/tracking';
 import { isGid, getIdFromGraphQLId } from '~/graphql_shared/utils';
 import { fetchUserCounts } from '~/super_sidebar/user_counts_fetch';
 import ReviewerDrawer from '~/merge_requests/components/reviewers/reviewer_drawer.vue';
@@ -35,6 +36,7 @@ export default {
     ApprovalSummary: () =>
       import('ee_component/merge_requests/components/reviewers/approval_summary.vue'),
   },
+  mixins: [InternalEvents.mixin()],
   props: {
     mediator: {
       type: Object,
@@ -191,6 +193,10 @@ export default {
     },
     toggleDrawerOpen(drawerOpen = !this.drawerOpen) {
       this.drawerOpen = drawerOpen;
+
+      if (drawerOpen) {
+        this.trackEvent('open_reviewer_sidebar_panel_in_mr');
+      }
     },
   },
 };
@@ -213,7 +219,7 @@ export default {
         category="tertiary"
         variant="confirm"
         class="gl-ml-2 !gl-text-sm"
-        data-testid="sidebar-reviewers-assign-buton"
+        data-testid="sidebar-reviewers-assign-button"
         @click="toggleDrawerOpen()"
       >
         {{ __('Assign') }}
diff --git a/ee/config/events/open_reviewer_sidebar_panel_in_mr.yml b/ee/config/events/open_reviewer_sidebar_panel_in_mr.yml
new file mode 100644
index 0000000000000000000000000000000000000000..8a945025371641dd8469ee178e3c42b1721d36bb
--- /dev/null
+++ b/ee/config/events/open_reviewer_sidebar_panel_in_mr.yml
@@ -0,0 +1,16 @@
+---
+description: User opens the reviewer sidebar panel on an MR
+internal_events: true
+action: open_reviewer_sidebar_panel_in_mr
+identifiers:
+- project
+- namespace
+- user
+product_group: code_review
+product_categories:
+- code_review_workflow
+milestone: '17.10'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183774
+tiers:
+- premium
+- ultimate
diff --git a/ee/config/metrics/counts_all/count_total_open_reviewer_sidebar_panel_in_mr.yml b/ee/config/metrics/counts_all/count_total_open_reviewer_sidebar_panel_in_mr.yml
new file mode 100644
index 0000000000000000000000000000000000000000..6d5d4150e484685555de83d0d12a01377a28248b
--- /dev/null
+++ b/ee/config/metrics/counts_all/count_total_open_reviewer_sidebar_panel_in_mr.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.count_total_open_reviewer_sidebar_panel_in_mr
+description: Count of the reviewer sidebar panel in an MR being opened by a user
+product_group: code_review
+product_categories:
+- code_review_workflow
+performance_indicator_type: []
+value_type: number
+status: active
+milestone: '17.10'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183774
+time_frame:
+- 28d
+- 7d
+- all
+data_source: internal_events
+data_category: optional
+tiers:
+- premium
+- ultimate
+events:
+- name: open_reviewer_sidebar_panel_in_mr
diff --git a/ee/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js b/ee/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js
new file mode 100644
index 0000000000000000000000000000000000000000..f60c057e0ed9d14aef5d6bda19089993413c00f4
--- /dev/null
+++ b/ee/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js
@@ -0,0 +1,88 @@
+import Vue from 'vue';
+import axios from 'axios';
+import AxiosMockAdapter from 'axios-mock-adapter';
+import VueApollo from 'vue-apollo';
+import { createMockSubscription as createMockApolloSubscription } from 'mock-apollo-client';
+import createMockApollo from 'helpers/mock_apollo_helper';
+import stubChildren from 'helpers/stub_children';
+import { mountExtended } from 'helpers/vue_test_utils_helper';
+import waitForPromises from 'helpers/wait_for_promises';
+import { useMockInternalEventsTracking } from 'helpers/tracking_internal_events_helper';
+import getMergeRequestReviewersQuery from '~/sidebar/queries/get_merge_request_reviewers.query.graphql';
+import mergeRequestReviewersUpdatedSubscription from '~/sidebar/queries/merge_request_reviewers.subscription.graphql';
+import SidebarReviewers from '~/sidebar/components/reviewers/sidebar_reviewers.vue';
+import SidebarMediator from '~/sidebar/sidebar_mediator';
+import { mockGetMergeRequestReviewers } from '../../mock_data';
+
+const { bindInternalEventDocument } = useMockInternalEventsTracking();
+
+Vue.use(VueApollo);
+
+describe('sidebar reviewers', () => {
+  const mockGQLQueries = [
+    [getMergeRequestReviewersQuery, jest.fn().mockResolvedValue(mockGetMergeRequestReviewers)],
+  ];
+
+  const mockedSubscription = createMockApolloSubscription();
+  const apolloMock = createMockApollo(mockGQLQueries);
+  let trackEventSpy;
+  let wrapper;
+  let mediator;
+  let axiosMock;
+
+  apolloMock.defaultClient.setRequestHandler(
+    mergeRequestReviewersUpdatedSubscription,
+    () => mockedSubscription,
+  );
+
+  const findAssignButton = () => wrapper.findByTestId('sidebar-reviewers-assign-button');
+
+  const createComponent = ({ props = {} } = {}) => {
+    wrapper = mountExtended(SidebarReviewers, {
+      apolloProvider: apolloMock,
+      propsData: {
+        issuableIid: '1',
+        issuableId: 1,
+        mediator,
+        field: '',
+        projectPath: 'projectPath',
+        changing: false,
+        ...props,
+      },
+      provide: {
+        projectPath: 'projectPath',
+        issuableId: 1,
+        issuableIid: 1,
+        multipleApprovalRulesAvailable: false,
+      },
+      stubs: {
+        ...stubChildren(SidebarReviewers),
+        GlButton: false,
+      },
+      // Attaching to document is required because this component emits something from the parent element :/
+      attachTo: document.body,
+    });
+
+    ({ trackEventSpy } = bindInternalEventDocument(wrapper.element));
+  };
+
+  beforeEach(() => {
+    axiosMock = new AxiosMockAdapter(axios);
+    mediator = new SidebarMediator({ currentUser: {} });
+  });
+
+  afterEach(() => {
+    axiosMock.restore();
+  });
+
+  it('sends the telemetry event when the reviewers panel is opened', async () => {
+    createComponent();
+    await waitForPromises();
+
+    const assign = findAssignButton();
+
+    assign.trigger('click');
+
+    expect(trackEventSpy).toHaveBeenCalledWith('open_reviewer_sidebar_panel_in_mr', {}, undefined);
+  });
+});
diff --git a/ee/spec/frontend/sidebar/mock_data.js b/ee/spec/frontend/sidebar/mock_data.js
index 35a4f8325785d854ade8a11fbf697fbd8c738ac1..c3ea18e298f9175738ce9a771e9cc0c5565ed88c 100644
--- a/ee/spec/frontend/sidebar/mock_data.js
+++ b/ee/spec/frontend/sidebar/mock_data.js
@@ -447,3 +447,35 @@ export const getHealthStatusQueryResponse = ({ state = 'opened', healthStatus =
     },
   };
 };
+
+export const mockGetMergeRequestReviewers = {
+  data: {
+    workspace: {
+      id: 'gid://gitlab/Project/1',
+      issuable: {
+        id: 'gid://gitlab/MergeRequest/1',
+        reviewers: {
+          nodes: [
+            {
+              id: 'gid://gitlab/User/1',
+              avatarUrl: 'image',
+              name: 'User',
+              username: 'username',
+              webUrl: 'https://example.com/username',
+              webPath: '/username',
+              status: null,
+              mergeRequestInteraction: {
+                canMerge: true,
+                canUpdate: true,
+                approved: true,
+                reviewState: 'APPROVED',
+                applicableApprovalRules: [{ id: 'gid://gitlab/ApprovalMergeRequestRule/1' }],
+              },
+            },
+          ],
+        },
+        userPermissions: { adminMergeRequest: true },
+      },
+    },
+  },
+};
diff --git a/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js b/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js
index 2e9126da81558581d92c8f26d4e5e481ad82478d..c541f0357bcc69193790c5092924472f903cacf2 100644
--- a/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js
+++ b/spec/frontend/sidebar/components/reviewers/sidebar_reviewers_spec.js
@@ -1,9 +1,9 @@
-import { shallowMount } from '@vue/test-utils';
 import Vue, { nextTick } from 'vue';
 import axios from 'axios';
 import AxiosMockAdapter from 'axios-mock-adapter';
 import VueApollo from 'vue-apollo';
 import createMockApollo from 'helpers/mock_apollo_helper';
+import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
 import SidebarReviewers from '~/sidebar/components/reviewers/sidebar_reviewers.vue';
 import SidebarService from '~/sidebar/services/sidebar_service';
 import SidebarMediator from '~/sidebar/sidebar_mediator';
@@ -21,8 +21,10 @@ describe('sidebar reviewers', () => {
   let mediator;
   let axiosMock;
 
+  const findAssignButton = () => wrapper.findByTestId('sidebar-reviewers-assign-button');
+
   const createComponent = (props) => {
-    wrapper = shallowMount(SidebarReviewers, {
+    wrapper = shallowMountExtended(SidebarReviewers, {
       apolloProvider: apolloMock,
       propsData: {
         issuableIid: '1',
@@ -67,7 +69,7 @@ describe('sidebar reviewers', () => {
     ${'shows'}         | ${true}   | ${true}
     ${'does not show'} | ${false}  | ${false}
   `('$copy Assign button when canUpdate is $canUpdate', ({ canUpdate, expected }) => {
-    wrapper = shallowMount(SidebarReviewers, {
+    wrapper = shallowMountExtended(SidebarReviewers, {
       apolloProvider: apolloMock,
       propsData: {
         issuableIid: '1',
@@ -93,7 +95,7 @@ describe('sidebar reviewers', () => {
       },
     });
 
-    expect(wrapper.find('[data-testid="sidebar-reviewers-assign-buton"]').exists()).toBe(expected);
+    expect(findAssignButton().exists()).toBe(expected);
   });
 
   it('calls the mediator when it saves the reviewers', () => {