diff --git a/.changeset/stupid-teachers-yell.md b/.changeset/stupid-teachers-yell.md
new file mode 100644
index 000000000000..a00ccceb5603
--- /dev/null
+++ b/.changeset/stupid-teachers-yell.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Cleans up content layer sync during builds and programmatic `sync()` calls
diff --git a/packages/astro/src/core/dev/container.ts b/packages/astro/src/core/dev/container.ts
index 0ca40cd74b3a..063681f2717c 100644
--- a/packages/astro/src/core/dev/container.ts
+++ b/packages/astro/src/core/dev/container.ts
@@ -120,6 +120,7 @@ export async function createContainer({
 		logger,
 		skip: {
 			content: true,
+			cleanup: true,
 		},
 		force: inlineConfig?.force,
 		manifest,
diff --git a/packages/astro/src/core/sync/index.ts b/packages/astro/src/core/sync/index.ts
index 823470e970b1..9e2a2de22d4c 100644
--- a/packages/astro/src/core/sync/index.ts
+++ b/packages/astro/src/core/sync/index.ts
@@ -45,6 +45,8 @@ export type SyncOptions = {
 	skip?: {
 		// Must be skipped in dev
 		content?: boolean;
+		// Cleanup can be skipped in dev as some state can be reused on updates
+		cleanup?: boolean;
 	};
 	manifest: ManifestData;
 };
@@ -141,6 +143,10 @@ export async function syncInternal({
 			store,
 		});
 		await contentLayer.sync();
+		if (!skip?.cleanup) {
+			// Free up memory (usually in builds since we only need to use this once)
+			contentLayer.dispose();
+		}
 		settings.timer.end('Sync content layer');
 	} else {
 		const paths = getContentPaths(settings.config, fs);