diff --git a/fixtures/ssr/server/render.js b/fixtures/ssr/server/render.js
index a6ee4decdd2..ababbc4ccd7 100644
--- a/fixtures/ssr/server/render.js
+++ b/fixtures/ssr/server/render.js
@@ -24,7 +24,7 @@ export default function render(url, res) {
     <App assets={assets} />,
     res,
     {
-      onReadyToStream() {
+      onCompleteShell() {
         // If something errored before we started streaming, we set the error code appropriately.
         res.statusCode = didError ? 500 : 200;
         res.setHeader('Content-type', 'text/html');
diff --git a/fixtures/ssr2/server/render.js b/fixtures/ssr2/server/render.js
index fdb545a073a..b5d919e82ca 100644
--- a/fixtures/ssr2/server/render.js
+++ b/fixtures/ssr2/server/render.js
@@ -43,7 +43,7 @@ module.exports = function render(url, res) {
     </DataProvider>,
     res,
     {
-      onReadyToStream() {
+      onCompleteShell() {
         // If something errored before we started streaming, we set the error code appropriately.
         res.statusCode = didError ? 500 : 200;
         res.setHeader('Content-type', 'text/html');
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index dd43cbd20d2..d786062043d 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -768,7 +768,7 @@ describe('ReactDOMFizzServer', () => {
         writableA,
         {
           identifierPrefix: 'A_',
-          onReadyToStream() {
+          onCompleteShell() {
             writableA.write('<div id="container-A">');
             startWriting();
             writableA.write('</div>');
@@ -788,7 +788,7 @@ describe('ReactDOMFizzServer', () => {
         writableB,
         {
           identifierPrefix: 'B_',
-          onReadyToStream() {
+          onCompleteShell() {
             writableB.write('<div id="container-B">');
             startWriting();
             writableB.write('</div>');
@@ -1029,7 +1029,7 @@ describe('ReactDOMFizzServer', () => {
         writable,
         {
           namespaceURI: 'http://www.w3.org/2000/svg',
-          onReadyToStream() {
+          onCompleteShell() {
             writable.write('<svg>');
             startWriting();
             writable.write('</svg>');
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js b/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
index 67ecb7f261e..42752a34c0b 100644
--- a/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
+++ b/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
@@ -28,7 +28,7 @@ type Options = {|
   namespaceURI?: string,
   progressiveChunkSize?: number,
   signal?: AbortSignal,
-  onReadyToStream?: () => void,
+  onCompleteShell?: () => void,
   onCompleteAll?: () => void,
   onError?: (error: mixed) => void,
 |};
@@ -56,7 +56,7 @@ function renderToReadableStream(
         options ? options.progressiveChunkSize : undefined,
         options ? options.onError : undefined,
         options ? options.onCompleteAll : undefined,
-        options ? options.onReadyToStream : undefined,
+        options ? options.onCompleteShell : undefined,
       );
       startWork(request);
     },
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerNode.js b/packages/react-dom/src/server/ReactDOMFizzServerNode.js
index ccfc91643a1..2bfb505ea06 100644
--- a/packages/react-dom/src/server/ReactDOMFizzServerNode.js
+++ b/packages/react-dom/src/server/ReactDOMFizzServerNode.js
@@ -32,7 +32,7 @@ type Options = {|
   identifierPrefix?: string,
   namespaceURI?: string,
   progressiveChunkSize?: number,
-  onReadyToStream?: () => void,
+  onCompleteShell?: () => void,
   onCompleteAll?: () => void,
   onError?: (error: mixed) => void,
 |};
@@ -57,7 +57,7 @@ function createRequestImpl(
     options ? options.progressiveChunkSize : undefined,
     options ? options.onError : undefined,
     options ? options.onCompleteAll : undefined,
-    options ? options.onReadyToStream : undefined,
+    options ? options.onCompleteShell : undefined,
   );
 }
 
diff --git a/packages/react-dom/src/server/ReactDOMLegacyServerBrowser.js b/packages/react-dom/src/server/ReactDOMLegacyServerBrowser.js
index 991c83e32e3..d05b44200e6 100644
--- a/packages/react-dom/src/server/ReactDOMLegacyServerBrowser.js
+++ b/packages/react-dom/src/server/ReactDOMLegacyServerBrowser.js
@@ -54,7 +54,7 @@ function renderToStringImpl(
   };
 
   let readyToStream = false;
-  function onReadyToStream() {
+  function onCompleteShell() {
     readyToStream = true;
   }
   const request = createRequest(
@@ -68,7 +68,7 @@ function renderToStringImpl(
     Infinity,
     onError,
     undefined,
-    onReadyToStream,
+    onCompleteShell,
   );
   startWork(request);
   // If anything suspended and is still pending, we'll abort it before writing.
diff --git a/packages/react-noop-renderer/src/ReactNoopServer.js b/packages/react-noop-renderer/src/ReactNoopServer.js
index 0ba00df7781..279c8b7b217 100644
--- a/packages/react-noop-renderer/src/ReactNoopServer.js
+++ b/packages/react-noop-renderer/src/ReactNoopServer.js
@@ -242,7 +242,7 @@ const ReactNoopServer = ReactFizzServer({
 
 type Options = {
   progressiveChunkSize?: number,
-  onReadyToStream?: () => void,
+  onCompleteShell?: () => void,
   onCompleteAll?: () => void,
   onError?: (error: mixed) => void,
 };
@@ -265,7 +265,7 @@ function render(children: React$Element<any>, options?: Options): Destination {
     options ? options.progressiveChunkSize : undefined,
     options ? options.onError : undefined,
     options ? options.onCompleteAll : undefined,
-    options ? options.onReadyToStream : undefined,
+    options ? options.onCompleteShell : undefined,
   );
   ReactNoopServer.startWork(request);
   ReactNoopServer.startFlowing(request);
diff --git a/packages/react-server/src/ReactFizzServer.js b/packages/react-server/src/ReactFizzServer.js
index f1463a1345d..ff8764ae069 100644
--- a/packages/react-server/src/ReactFizzServer.js
+++ b/packages/react-server/src/ReactFizzServer.js
@@ -190,10 +190,10 @@ export opaque type Request = {
   // onCompleteAll is called when all pending task is done but it may not have flushed yet.
   // This is a good time to start writing if you want only HTML and no intermediate steps.
   onCompleteAll: () => void,
-  // onReadyToStream is called when there is at least a root fallback ready to show.
+  // onCompleteShell is called when there is at least a root fallback ready to show.
   // Typically you don't need this callback because it's best practice to always have a
   // root fallback ready so there's no need to wait.
-  onReadyToStream: () => void,
+  onCompleteShell: () => void,
 };
 
 // This is a default heuristic for how to split up the HTML content into progressive
@@ -227,7 +227,7 @@ export function createRequest(
   progressiveChunkSize: void | number,
   onError: void | ((error: mixed) => void),
   onCompleteAll: void | (() => void),
-  onReadyToStream: void | (() => void),
+  onCompleteShell: void | (() => void),
 ): Request {
   const pingedTasks = [];
   const abortSet: Set<Task> = new Set();
@@ -250,7 +250,7 @@ export function createRequest(
     partialBoundaries: [],
     onError: onError === undefined ? defaultErrorHandler : onError,
     onCompleteAll: onCompleteAll === undefined ? noop : onCompleteAll,
-    onReadyToStream: onReadyToStream === undefined ? noop : onReadyToStream,
+    onCompleteShell: onCompleteShell === undefined ? noop : onCompleteShell,
   };
   // This segment represents the root fallback.
   const rootSegment = createPendingSegment(request, 0, null, rootFormatContext);
@@ -1370,8 +1370,8 @@ function finishedTask(
     }
     request.pendingRootTasks--;
     if (request.pendingRootTasks === 0) {
-      const onReadyToStream = request.onReadyToStream;
-      onReadyToStream();
+      const onCompleteShell = request.onCompleteShell;
+      onCompleteShell();
     }
   } else {
     boundary.pendingTasks--;