diff --git a/.changeset/shaggy-walls-wave.md b/.changeset/shaggy-walls-wave.md
new file mode 100644
index 000000000000..664c7402e896
--- /dev/null
+++ b/.changeset/shaggy-walls-wave.md
@@ -0,0 +1,5 @@
+---
+"@sveltejs/kit": major
+---
+
+fix: tsconfig includes should cover svelte.config.js
\ No newline at end of file
diff --git a/packages/kit/src/core/sync/write_tsconfig.js b/packages/kit/src/core/sync/write_tsconfig.js
index 0bf360ab77d1..fdbb99973a23 100644
--- a/packages/kit/src/core/sync/write_tsconfig.js
+++ b/packages/kit/src/core/sync/write_tsconfig.js
@@ -58,6 +58,7 @@ export function get_tsconfig(kit) {
 		'ambient.d.ts', // careful: changing this name would be a breaking change, because it's referenced in the service-workers documentation
 		'non-ambient.d.ts',
 		'./types/**/$types.d.ts',
+		config_relative('svelte.config.js'),
 		config_relative('vite.config.js'),
 		config_relative('vite.config.ts')
 	]);
diff --git a/packages/kit/src/core/sync/write_tsconfig.spec.js b/packages/kit/src/core/sync/write_tsconfig.spec.js
index fbfa18cc97b9..ebabcb6c9278 100644
--- a/packages/kit/src/core/sync/write_tsconfig.spec.js
+++ b/packages/kit/src/core/sync/write_tsconfig.spec.js
@@ -77,6 +77,7 @@ test('Creates tsconfig include from kit.files', () => {
 		'ambient.d.ts',
 		'non-ambient.d.ts',
 		'./types/**/$types.d.ts',
+		'../svelte.config.js',
 		'../vite.config.js',
 		'../vite.config.ts',
 		'../app/**/*.js',