diff --git a/packages/react-cosmos-core/src/renderer/rendererConnect.ts b/packages/react-cosmos-core/src/renderer/rendererConnect.ts
index da32e70be2..3b450aa319 100644
--- a/packages/react-cosmos-core/src/renderer/rendererConnect.ts
+++ b/packages/react-cosmos-core/src/renderer/rendererConnect.ts
@@ -1,5 +1,9 @@
 import { FixtureState } from '../fixtureState/types.js';
-import { FixtureId, FixtureList } from '../userModules/fixtureTypes.js';
+import {
+  FixtureId,
+  FixtureList,
+  FixtureListItem,
+} from '../userModules/fixtureTypes.js';
 
 // FYI: Renderer ids are self assigned in remote environments, so uniqueness
 // cannot be established by consensus
@@ -73,6 +77,14 @@ export type FixtureListUpdateResponse = {
   };
 };
 
+export type FixtureLoadedResponse = {
+  type: 'fixtureLoaded';
+  payload: {
+    rendererId: RendererId;
+    fixture: FixtureListItem;
+  };
+};
+
 // Caused by an organic state change inside the renderer. Also dispatched
 // after a fixtureSelect request, when rendering stateful components, as their
 // initial state is read.
@@ -98,6 +110,7 @@ export type PlaygroundCommandResponse = {
 export type RendererResponse =
   | RendererReadyResponse
   | RendererErrorResponse
+  | FixtureLoadedResponse
   | FixtureListUpdateResponse
   | FixtureStateChangeResponse
   | PlaygroundCommandResponse;
diff --git a/packages/react-cosmos-renderer/src/__tests__/fixtureSelect.ts b/packages/react-cosmos-renderer/src/__tests__/fixtureSelect.ts
index 4e2c0cb09a..7b07d3af5a 100644
--- a/packages/react-cosmos-renderer/src/__tests__/fixtureSelect.ts
+++ b/packages/react-cosmos-renderer/src/__tests__/fixtureSelect.ts
@@ -112,3 +112,35 @@ testRenderer(
     );
   }
 );
+
+testRenderer(
+  'returns fixtureLoaded response for single fixture',
+  { rendererId, fixtures },
+  async ({ selectFixture, fixtureLoaded }) => {
+    selectFixture({
+      rendererId,
+      fixtureId: { path: 'second' },
+      fixtureState: {},
+    });
+    await fixtureLoaded({
+      rendererId,
+      fixture: { type: 'single' },
+    });
+  }
+);
+
+testRenderer(
+  'returns fixtureLoaded response for multi fixture',
+  { rendererId, fixtures },
+  async ({ selectFixture, fixtureLoaded }) => {
+    selectFixture({
+      rendererId,
+      fixtureId: { path: 'first', name: 'one' },
+      fixtureState: {},
+    });
+    await fixtureLoaded({
+      rendererId,
+      fixture: { type: 'multi', fixtureNames: ['one'] },
+    });
+  }
+);
diff --git a/packages/react-cosmos-renderer/src/__tests__/fixtureSelectLazy.ts b/packages/react-cosmos-renderer/src/__tests__/fixtureSelectLazy.ts
new file mode 100644
index 0000000000..4f9e6b46e6
--- /dev/null
+++ b/packages/react-cosmos-renderer/src/__tests__/fixtureSelectLazy.ts
@@ -0,0 +1,44 @@
+import { uuid } from 'react-cosmos-core';
+import { testRenderer } from '../testHelpers/testRenderer.js';
+import { wrapActSetTimeout } from '../testHelpers/wrapActSetTimeout.js';
+import { wrapDefaultExport } from '../testHelpers/wrapDefaultExport.js';
+
+beforeAll(wrapActSetTimeout);
+
+const rendererId = uuid();
+const fixtures = wrapDefaultExport({
+  first: { one: 'First' },
+  second: 'Second',
+});
+
+testRenderer(
+  'returns lazy fixtureLoaded response for single fixture',
+  { rendererId, fixtures, lazy: true },
+  async ({ selectFixture, fixtureLoaded }) => {
+    selectFixture({
+      rendererId,
+      fixtureId: { path: 'second' },
+      fixtureState: {},
+    });
+    await fixtureLoaded({
+      rendererId,
+      fixture: { type: 'single' },
+    });
+  }
+);
+
+testRenderer(
+  'returns lazy fixtureLoaded response for multi fixture',
+  { rendererId, fixtures, lazy: true },
+  async ({ selectFixture, fixtureLoaded }) => {
+    selectFixture({
+      rendererId,
+      fixtureId: { path: 'first', name: 'one' },
+      fixtureState: {},
+    });
+    await fixtureLoaded({
+      rendererId,
+      fixture: { type: 'multi', fixtureNames: ['one'] },
+    });
+  }
+);
diff --git a/packages/react-cosmos-renderer/src/fixtureModule/FixtureProvider.tsx b/packages/react-cosmos-renderer/src/fixtureModule/FixtureProvider.tsx
index fe8130f0a7..5abafe7b69 100644
--- a/packages/react-cosmos-renderer/src/fixtureModule/FixtureProvider.tsx
+++ b/packages/react-cosmos-renderer/src/fixtureModule/FixtureProvider.tsx
@@ -45,6 +45,16 @@ export function FixtureProvider(props: Props) {
     }
   }, [props.fixtureId.path, props.fixtureItem, props.lazy, setLazyItems]);
 
+  React.useEffect(() => {
+    rendererConnect.postMessage({
+      type: 'fixtureLoaded',
+      payload: {
+        rendererId,
+        fixture: props.fixtureItem,
+      },
+    });
+  }, [props.fixtureItem, rendererConnect, rendererId]);
+
   React.useEffect(() => {
     if (!isEqual(state.fixtureState, state.syncedFixtureState)) {
       rendererConnect.postMessage({
diff --git a/packages/react-cosmos-renderer/src/testHelpers/createRendererConnectTestApi.ts b/packages/react-cosmos-renderer/src/testHelpers/createRendererConnectTestApi.ts
index 1722b6391c..25ca5130ac 100644
--- a/packages/react-cosmos-renderer/src/testHelpers/createRendererConnectTestApi.ts
+++ b/packages/react-cosmos-renderer/src/testHelpers/createRendererConnectTestApi.ts
@@ -2,6 +2,7 @@ import until from 'async-until';
 import { findLast } from 'lodash-es';
 import {
   FixtureListUpdateResponse,
+  FixtureLoadedResponse,
   FixtureState,
   FixtureStateChangeResponse,
   ReloadRendererRequest,
@@ -23,6 +24,7 @@ export type RendererConnectTestApi = {
   fixtureListUpdate: (
     payload: FixtureListUpdateResponse['payload']
   ) => Promise<void>;
+  fixtureLoaded: (payload: FixtureLoadedResponse['payload']) => Promise<void>;
   fixtureStateChange: (
     payload: FixtureStateChangeResponse['payload']
   ) => Promise<void>;
@@ -43,6 +45,7 @@ export function createRendererConnectTestApi(args: {
     setFixtureState,
     rendererReady,
     fixtureListUpdate,
+    fixtureLoaded,
     fixtureStateChange,
     getLastFixtureState,
     clearResponses: args.clearResponses,
@@ -98,6 +101,13 @@ export function createRendererConnectTestApi(args: {
     });
   }
 
+  async function fixtureLoaded(payload: FixtureLoadedResponse['payload']) {
+    await untilResponse({
+      type: 'fixtureLoaded',
+      payload,
+    });
+  }
+
   async function fixtureStateChange(
     payload: FixtureStateChangeResponse['payload']
   ) {