diff --git a/.changeset/tasty-flies-love.md b/.changeset/tasty-flies-love.md
new file mode 100644
index 000000000..3a3a14a45
--- /dev/null
+++ b/.changeset/tasty-flies-love.md
@@ -0,0 +1,5 @@
+---
+"eslint-plugin-svelte": patch
+---
+
+fix: crash with non svelte files in `svelte/no-unused-class-name`
diff --git a/src/rules/no-unused-class-name.ts b/src/rules/no-unused-class-name.ts
index 541f54a05..8d7100fb5 100644
--- a/src/rules/no-unused-class-name.ts
+++ b/src/rules/no-unused-class-name.ts
@@ -27,6 +27,9 @@ export default createRule("no-unused-class-name", {
     type: "suggestion",
   },
   create(context) {
+    if (!context.parserServices.isSvelte) {
+      return {}
+    }
     const classesUsedInTemplate: Record<string, SourceLocation> = {}
 
     return {
diff --git a/tests/fixtures/rules/no-unused-class-name/valid/test-input.js b/tests/fixtures/rules/no-unused-class-name/valid/test-input.js
new file mode 100644
index 000000000..17d8c7949
--- /dev/null
+++ b/tests/fixtures/rules/no-unused-class-name/valid/test-input.js
@@ -0,0 +1 @@
+console.log("a")