diff --git a/packages/adapter-static/README.md b/packages/adapter-static/README.md
index 7d7ed7ecf54a5..d6350da0cbccc 100644
--- a/packages/adapter-static/README.md
+++ b/packages/adapter-static/README.md
@@ -38,6 +38,25 @@ The directory to write static assets (the contents of `static`, plus client-side
 
 Specify a fallback page for SPA mode, e.g. `index.html` or `200.html` or `404.html`.
 
+### outputFileName
+
+A optional function that is called per entry to return the destination to write to.
+
+Default value:
+
+```javascript
+/** @type {(opts: {path: string, is_html: boolean}) => string} */
+function default_output_file_name({ path, is_html }) {
+	if (!is_html) return path;
+
+	const parts = path.split('/');
+	if (parts[parts.length - 1] === 'index.html') return path;
+
+	parts.push('index.html');
+	return parts.join('/');
+}
+```
+
 ## SPA mode
 
 You can use `adapter-static` to create a single-page app or SPA by specifying a **fallback page**.
diff --git a/packages/adapter-static/index.d.ts b/packages/adapter-static/index.d.ts
index 1f298a4a6f389..92e3475640aa8 100644
--- a/packages/adapter-static/index.d.ts
+++ b/packages/adapter-static/index.d.ts
@@ -4,6 +4,7 @@ interface AdapterOptions {
 	pages?: string;
 	assets?: string;
 	fallback?: string;
+	outputFileName?: (opts: { path: string, is_html: boolean }) => string;
 }
 
 declare function plugin(options?: AdapterOptions): Adapter;
diff --git a/packages/adapter-static/index.js b/packages/adapter-static/index.js
index e1cc80ce042f3..756bf824029b2 100644
--- a/packages/adapter-static/index.js
+++ b/packages/adapter-static/index.js
@@ -1,8 +1,17 @@
-/** @type {import('.')} */
-export default function ({ pages = 'build', assets = pages, fallback } = {}) {
+/**
+ * @param {{
+ *   pages?: string;
+ *   assets?: string;
+ *   fallback?: string;
+ *   outputFileName?: (opts: {path: string, is_html: boolean}) => string;
+ * }} [opts]
+ */
+export default function({ pages = 'build', assets = pages, fallback, outputFileName } = {}) {
+	/** @type {import('@sveltejs/kit').Adapter} */
 	return {
 		name: '@sveltejs/adapter-static',
 
+		/** @type {import('@sveltejs/kit').Adapter['adapt']} */
 		async adapt({ utils }) {
 			utils.rimraf(assets);
 			utils.rimraf(pages);
@@ -13,7 +22,8 @@ export default function ({ pages = 'build', assets = pages, fallback } = {}) {
 			await utils.prerender({
 				fallback,
 				all: !fallback,
-				dest: pages
+				dest: pages,
+				output_file_name: outputFileName
 			});
 		}
 	};
diff --git a/packages/adapter-static/test/apps/spa-entry-name/.gitignore b/packages/adapter-static/test/apps/spa-entry-name/.gitignore
new file mode 100644
index 0000000000000..0a4623184983b
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/.gitignore
@@ -0,0 +1,5 @@
+.DS_Store
+node_modules
+/.svelte-kit
+/build
+/functions
diff --git a/packages/adapter-static/test/apps/spa-entry-name/.npmrc b/packages/adapter-static/test/apps/spa-entry-name/.npmrc
new file mode 100644
index 0000000000000..b6f27f1359546
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/.npmrc
@@ -0,0 +1 @@
+engine-strict=true
diff --git a/packages/adapter-static/test/apps/spa-entry-name/README.md b/packages/adapter-static/test/apps/spa-entry-name/README.md
new file mode 100644
index 0000000000000..82510ca06f504
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/README.md
@@ -0,0 +1,38 @@
+# create-svelte
+
+Everything you need to build a Svelte project, powered by [`create-svelte`](https://github.com/sveltejs/kit/tree/master/packages/create-svelte);
+
+## Creating a project
+
+If you're seeing this, you've probably already done this step. Congrats!
+
+```bash
+# create a new project in the current directory
+npm init svelte@next
+
+# create a new project in my-app
+npm init svelte@next my-app
+```
+
+> Note: the `@next` is temporary
+
+## Developing
+
+Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+
+```bash
+npm run dev
+
+# or start the server and open the app in a new browser tab
+npm run dev -- --open
+```
+
+## Building
+
+Before creating a production version of your app, install an [adapter](https://kit.svelte.dev/docs#adapters) for your target environment. Then:
+
+```bash
+npm run build
+```
+
+> You can preview the built app with `npm run preview`, regardless of whether you installed an adapter. This should _not_ be used to serve your app in production.
diff --git a/packages/adapter-static/test/apps/spa-entry-name/jsconfig.json b/packages/adapter-static/test/apps/spa-entry-name/jsconfig.json
new file mode 100644
index 0000000000000..893781f65ca0c
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/jsconfig.json
@@ -0,0 +1,9 @@
+{
+	"compilerOptions": {
+		"baseUrl": ".",
+		"paths": {
+			"$lib/*": ["src/lib/*"]
+		}
+	},
+	"include": ["src/**/*.d.ts", "src/**/*.js", "src/**/*.svelte"]
+}
diff --git a/packages/adapter-static/test/apps/spa-entry-name/package.json b/packages/adapter-static/test/apps/spa-entry-name/package.json
new file mode 100644
index 0000000000000..c39d2a71cee10
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/package.json
@@ -0,0 +1,15 @@
+{
+	"name": "~TODO~",
+	"version": "0.0.1",
+	"scripts": {
+		"dev": "../../../../kit/svelte-kit.js dev",
+		"build": "../../../../kit/svelte-kit.js build",
+		"start": "../../../../kit/svelte-kit.js start"
+	},
+	"devDependencies": {
+		"@sveltejs/adapter-node": "next",
+		"@sveltejs/kit": "workspace:*",
+		"svelte": "^3.40.0"
+	},
+	"type": "module"
+}
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/app.html b/packages/adapter-static/test/apps/spa-entry-name/src/app.html
new file mode 100644
index 0000000000000..ab9a75726ecc6
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/app.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		%svelte.head%
+	</head>
+	<body>
+		<div id="svelte">%svelte.body%</div>
+	</body>
+</html>
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/global.d.ts b/packages/adapter-static/test/apps/spa-entry-name/src/global.d.ts
new file mode 100644
index 0000000000000..63908c66cfd4a
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/global.d.ts
@@ -0,0 +1 @@
+/// <reference types="@sveltejs/kit" />
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/routes/__layout.svelte b/packages/adapter-static/test/apps/spa-entry-name/src/routes/__layout.svelte
new file mode 100644
index 0000000000000..2633c3c802ca3
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/routes/__layout.svelte
@@ -0,0 +1,7 @@
+<nav>
+	<a href="/">home</a>
+	<a href="/page">page</a>
+	<a href="/about.html">about</a>
+</nav>
+
+<slot></slot>
\ No newline at end of file
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/routes/about.html.svelte b/packages/adapter-static/test/apps/spa-entry-name/src/routes/about.html.svelte
new file mode 100644
index 0000000000000..eaafdd9c712ae
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/routes/about.html.svelte
@@ -0,0 +1,7 @@
+<script context="module">
+	export const prerender = true;
+</script>
+
+<h1>This page was prerendered</h1>
+
+<h2>about</h2>
\ No newline at end of file
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/routes/index.svelte b/packages/adapter-static/test/apps/spa-entry-name/src/routes/index.svelte
new file mode 100644
index 0000000000000..913f0784cbb66
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/routes/index.svelte
@@ -0,0 +1 @@
+<h1>This page was not prerendered</h1>
\ No newline at end of file
diff --git a/packages/adapter-static/test/apps/spa-entry-name/src/routes/page.svelte b/packages/adapter-static/test/apps/spa-entry-name/src/routes/page.svelte
new file mode 100644
index 0000000000000..73a4c7838d16f
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/src/routes/page.svelte
@@ -0,0 +1,7 @@
+<script context="module">
+	export const prerender = true;
+</script>
+
+<h1>This page was prerendered</h1>
+
+<h2>page</h2>
\ No newline at end of file
diff --git a/packages/adapter-static/test/apps/spa-entry-name/svelte.config.js b/packages/adapter-static/test/apps/spa-entry-name/svelte.config.js
new file mode 100644
index 0000000000000..82874d4bb4492
--- /dev/null
+++ b/packages/adapter-static/test/apps/spa-entry-name/svelte.config.js
@@ -0,0 +1,23 @@
+import { format, parse } from 'path';
+import adapter from '../../../index.js';
+
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+	kit: {
+		adapter: adapter({
+			fallback: '200.html',
+			outputFileName: ({ path, is_html }) => {
+				if (!is_html) return path;
+
+				let { root, dir, name, ext } = parse(path);
+
+				if (!ext) ext = '.html';
+
+				return format({ root, dir, name, ext });
+			}
+		}),
+		target: '#svelte'
+	}
+};
+
+export default config;
diff --git a/packages/adapter-static/test/test.js b/packages/adapter-static/test/test.js
index 16629cfa9469c..8fbb52f5e83c5 100644
--- a/packages/adapter-static/test/test.js
+++ b/packages/adapter-static/test/test.js
@@ -36,3 +36,28 @@ run('spa', (test) => {
 		assert.equal(await page.textContent('h1'), '404');
 	});
 });
+
+run('spa-entry-name', (test) => {
+	test('generates a fallback page', ({ cwd }) => {
+		assert.ok(fs.existsSync(`${cwd}/build/200.html`));
+	});
+
+	test('does not prerender pages without prerender=true', ({ cwd }) => {
+		assert.ok(!fs.existsSync(`${cwd}/build/index.html`));
+	});
+
+	test('prerenders page with prerender=true', ({ cwd }) => {
+		assert.ok(fs.existsSync(`${cwd}/build/about.html`));
+		assert.ok(fs.existsSync(`${cwd}/build/page.html`));
+	});
+
+	test('renders content in fallback page when JS runs', async ({ base, page }) => {
+		await page.goto(base);
+		assert.equal(await page.textContent('h1'), 'This page was not prerendered');
+	});
+
+	test('renders error page for missing page', async ({ base, page }) => {
+		await page.goto(`${base}/nosuchpage`);
+		assert.equal(await page.textContent('h1'), '404');
+	});
+});