diff --git a/.changeset/eighty-laws-brake.md b/.changeset/eighty-laws-brake.md
new file mode 100644
index 000000000..b4947f1aa
--- /dev/null
+++ b/.changeset/eighty-laws-brake.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Update `chunkFileNames` to avoid emitting invalid characters
diff --git a/packages/astro/src/core/build/static-build.ts b/packages/astro/src/core/build/static-build.ts
index 0bfb4e3ae..407e0ecde 100644
--- a/packages/astro/src/core/build/static-build.ts
+++ b/packages/astro/src/core/build/static-build.ts
@@ -172,7 +172,21 @@ async function ssrBuild(
 					format: 'esm',
 					// Server chunks can't go in the assets (_astro) folder
 					// We need to keep these separate
-					chunkFileNames: `chunks/[name].[hash].mjs`,
+					chunkFileNames(chunkInfo) {
+						const { name } = chunkInfo;
+						// Sometimes chunks have the `@_@astro` suffix due to SSR logic. Remove it!
+						// TODO: refactor our build logic to avoid this
+						if (name.includes(ASTRO_PAGE_EXTENSION_POST_PATTERN)) {
+							const [sanitizedName] = name.split(ASTRO_PAGE_EXTENSION_POST_PATTERN);
+							return `chunks/${sanitizedName}_[hash].mjs`
+						}
+						// Injected routes include "pages/[name].[ext]" already. Clean those up!
+						if (name.startsWith('pages/')) {
+							const sanitizedName = name.split('.')[0];
+							return `chunks/${sanitizedName}_[hash].mjs`
+						}
+						return `chunks/[name]_[hash].mjs`
+					},
 					assetFileNames: `${settings.config.build.assets}/[name].[hash][extname]`,
 					...viteConfig.build?.rollupOptions?.output,
 					entryFileNames(chunkInfo) {
@@ -189,7 +203,7 @@ async function ssrBuild(
 						} else if (chunkInfo.facadeModuleId === RESOLVED_RENDERERS_MODULE_ID) {
 							return 'renderers.mjs';
 						} else if (chunkInfo.facadeModuleId === RESOLVED_SSR_MANIFEST_VIRTUAL_MODULE_ID) {
-							return 'manifest.[hash].mjs';
+							return 'manifest_[hash].mjs';
 						} else {
 							return '[name].mjs';
 						}