diff --git a/.changeset/gentle-rocks-run.md b/.changeset/gentle-rocks-run.md
new file mode 100644
index 000000000000..5730b5b8f60d
--- /dev/null
+++ b/.changeset/gentle-rocks-run.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/package': patch
+---
+
+[feat] warn if svelte not found in dependencies or peerDependencies
diff --git a/packages/package/src/index.js b/packages/package/src/index.js
index d751537bf1cf..e7af57df8140 100644
--- a/packages/package/src/index.js
+++ b/packages/package/src/index.js
@@ -32,6 +32,12 @@ export async function build(config, cwd = process.cwd()) {
 
 	const pkg = generate_pkg(cwd, files);
 
+	if (!pkg.dependencies?.svelte && !pkg.peerDependencies?.svelte) {
+		console.warn(
+			'Svelte libraries should include "svelte" in either "dependencies" or "peerDependencies".'
+		);
+	}
+
 	if (!pkg.svelte && files.some((file) => file.is_svelte)) {
 		// Several heuristics in Kit/vite-plugin-svelte to tell Vite to mark Svelte packages
 		// rely on the "svelte" property. Vite/Rollup/Webpack plugin can all deal with it.