diff --git a/.changeset/neat-tigers-float.md b/.changeset/neat-tigers-float.md
new file mode 100644
index 000000000000..10326f6fef80
--- /dev/null
+++ b/.changeset/neat-tigers-float.md
@@ -0,0 +1,23 @@
+---
+'@astrojs/sitemap': minor
+---
+
+Customize the filenames of sitemap XML files generated by the `@astro/sitemap` integration by setting `filenameBase` in the integration configuration settings. This may be useful when deploying an Astro site at a path on a domain with preexisting sitemap files.
+
+Generated sitemap files will appear at `/sitemap-0.xml` and `/sitemap-index.xml` by default, which may conflict with preexisting files. Set `filenameBase` to a custom value to avoid that if so:
+
+```js
+  import { defineConfig } from 'astro/config';
+  import sitemap from '@astrojs/sitemap';
+
+  export default defineConfig({
+    site: 'https://example.com',
+    integrations: [
+      sitemap({
+        filenameBase: 'astronomy-sitemap',
+      }),
+    ],
+  });
+```
+
+This will yield sitemap and index files as `https://example.com/astronomy-sitemap-0.xml` and `https://example.com/astronomy-sitemap-index.xml`.
diff --git a/packages/integrations/sitemap/src/config-defaults.ts b/packages/integrations/sitemap/src/config-defaults.ts
index 3d56483e196b..8d854c7a98e0 100644
--- a/packages/integrations/sitemap/src/config-defaults.ts
+++ b/packages/integrations/sitemap/src/config-defaults.ts
@@ -1,5 +1,6 @@
 import type { SitemapOptions } from './index.js';
 
 export const SITEMAP_CONFIG_DEFAULTS = {
+	filenameBase: 'sitemap',
 	entryLimit: 45000,
 } satisfies SitemapOptions;
diff --git a/packages/integrations/sitemap/src/index.ts b/packages/integrations/sitemap/src/index.ts
index 9bbd39e4a71f..51b34abd5a4a 100644
--- a/packages/integrations/sitemap/src/index.ts
+++ b/packages/integrations/sitemap/src/index.ts
@@ -18,6 +18,7 @@ export type LinkItem = LinkItemBase;
 
 export type SitemapOptions =
 	| {
+			filenameBase?: string;
 			filter?(page: string): boolean;
 			customPages?: string[];
 
@@ -46,7 +47,6 @@ function formatConfigErrorMessage(err: ZodError) {
 }
 
 const PKG_NAME = '@astrojs/sitemap';
-const OUTFILE = 'sitemap-index.xml';
 const STATUS_CODE_PAGES = new Set(['404', '500']);
 
 const isStatusCodePage = (locales: string[]) => {
@@ -88,8 +88,9 @@ const createPlugin = (options?: SitemapOptions): AstroIntegration => {
 
 					const opts = validateOptions(config.site, options);
 
-					const { filter, customPages, serialize, entryLimit } = opts;
+					const { filenameBase, filter, customPages, serialize, entryLimit } = opts;
 
+					const outFile = `${filenameBase}-index.xml`;
 					const finalSiteUrl = new URL(config.base, config.site);
 					const shouldIgnoreStatus = isStatusCodePage(Object.keys(opts.i18n?.locales ?? {}));
 					let pageUrls = pages
@@ -144,7 +145,7 @@ const createPlugin = (options?: SitemapOptions): AstroIntegration => {
 					}
 
 					if (pageUrls.length === 0) {
-						logger.warn(`No pages found!\n\`${OUTFILE}\` not created.`);
+						logger.warn(`No pages found!\n\`${outFile}\` not created.`);
 						return;
 					}
 
@@ -173,6 +174,7 @@ const createPlugin = (options?: SitemapOptions): AstroIntegration => {
 					const xslURL = opts.xslURL ? new URL(opts.xslURL, finalSiteUrl).href : undefined;
 					await writeSitemap(
 						{
+							filenameBase: filenameBase,
 							hostname: finalSiteUrl.href,
 							destinationDir: destDir,
 							publicBasePath: config.base,
@@ -182,7 +184,7 @@ const createPlugin = (options?: SitemapOptions): AstroIntegration => {
 						},
 						config,
 					);
-					logger.info(`\`${OUTFILE}\` created at \`${path.relative(process.cwd(), destDir)}\``);
+					logger.info(`\`${outFile}\` created at \`${path.relative(process.cwd(), destDir)}\``);
 				} catch (err) {
 					if (err instanceof ZodError) {
 						logger.warn(formatConfigErrorMessage(err));
diff --git a/packages/integrations/sitemap/src/schema.ts b/packages/integrations/sitemap/src/schema.ts
index ba5438452395..0ab9d672d49f 100644
--- a/packages/integrations/sitemap/src/schema.ts
+++ b/packages/integrations/sitemap/src/schema.ts
@@ -6,6 +6,7 @@ const localeKeySchema = z.string().min(1);
 
 export const SitemapOptionsSchema = z
 	.object({
+		filenameBase: z.string().optional().default(SITEMAP_CONFIG_DEFAULTS.filenameBase),
 		filter: z.function().args(z.string()).returns(z.boolean()).optional(),
 		customPages: z.string().url().array().optional(),
 		canonicalURL: z.string().url().optional(),
diff --git a/packages/integrations/sitemap/src/write-sitemap.ts b/packages/integrations/sitemap/src/write-sitemap.ts
index 85efe4b263d5..939bd91be381 100644
--- a/packages/integrations/sitemap/src/write-sitemap.ts
+++ b/packages/integrations/sitemap/src/write-sitemap.ts
@@ -11,6 +11,7 @@ import type { AstroConfig } from 'astro';
 import type { SitemapItem } from './index.js';
 
 type WriteSitemapConfig = {
+	filenameBase: string;
 	hostname: string;
 	sitemapHostname?: string;
 	sourceData: SitemapItem[];
@@ -23,6 +24,7 @@ type WriteSitemapConfig = {
 // adapted from sitemap.js/sitemap-simple
 export async function writeSitemap(
 	{
+		filenameBase,
 		hostname,
 		sitemapHostname = hostname,
 		sourceData,
@@ -43,7 +45,7 @@ export async function writeSitemap(
 				hostname,
 				xslUrl,
 			});
-			const path = `./sitemap-${i}.xml`;
+			const path = `./${filenameBase}-${i}.xml`;
 			const writePath = resolve(destinationDir, path);
 			if (!publicBasePath.endsWith('/')) {
 				publicBasePath += '/';
@@ -68,6 +70,6 @@ export async function writeSitemap(
 	});
 
 	const src = Readable.from(sourceData);
-	const indexPath = resolve(destinationDir, `./sitemap-index.xml`);
+	const indexPath = resolve(destinationDir, `./${filenameBase}-index.xml`);
 	return promisify(pipeline)(src, sitemapAndIndexStream, createWriteStream(indexPath));
 }
diff --git a/packages/integrations/sitemap/test/config.test.js b/packages/integrations/sitemap/test/config.test.js
index fef9552dd9db..aaf66abc221e 100644
--- a/packages/integrations/sitemap/test/config.test.js
+++ b/packages/integrations/sitemap/test/config.test.js
@@ -80,4 +80,30 @@ describe('Config', () => {
 			);
 		});
 	});
+
+	describe('Configuring the filename', () => {
+		before(async () => {
+			fixture = await loadFixture({
+				root: './fixtures/static/',
+				integrations: [
+					sitemap({
+						filter: (page) => page === 'http://example.com/one/',
+						filenameBase: 'my-sitemap',
+					}),
+				],
+			});
+			await fixture.build();
+		});
+
+		it('filenameBase: Sets the generated sitemap filename', async () => {
+			const data = await readXML(fixture.readFile('/my-sitemap-0.xml'));
+			const urls = data.urlset.url;
+			assert.equal(urls.length, 1);
+
+			const indexData = await readXML(fixture.readFile('/my-sitemap-index.xml'));
+			const sitemapUrls = indexData.sitemapindex.sitemap;
+			assert.equal(sitemapUrls.length, 1);
+			assert.equal(sitemapUrls[0].loc[0], 'http://example.com/my-sitemap-0.xml');
+		});
+	});
 });