diff --git a/package.json b/package.json
index f60199d..e1c0ee1 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,8 @@
   ],
   "activationEvents": [
     "onLanguage:ruby",
-    "workspaceContains:Gemfile.lock"
+    "workspaceContains:Gemfile.lock",
+    "workspaceContains:**/.standard.yml"
   ],
   "main": "./out/extension",
   "contributes": {
@@ -102,6 +103,15 @@
             "type": "string",
             "default": "",
             "markdownDescription": "Absolute path to standardrb executable. Overrides default search order and, if missing, will not run Standard via Bundler or a `standardrb` executable on your PATH.\n\nSupports variables `${userHome}`, `${pathSeparator}`, and `${cwd}`"
+          },
+          "standardRuby.additionalLanguages": {
+            "order": 4,
+            "type": "array",
+            "items": {
+              "type": "string"
+            },
+            "default": [],
+            "markdownDescription": "Additional [VS Code language identifiers](https://code.visualstudio.com/docs/languages/identifiers) to send to the Standard Ruby language server, in addition to `ruby` and `Gemfile`.\n\nUse this to lint non-Ruby files that a custom RuboCop cop handles via `on_other_file` — for example `[\"yaml\"]` for a plugin that validates `data/**/*.yml`, or `[\"erb\"]` for an ERB linter.\n\n**Important:** Standard's built-in cops must be excluded for these files in your project config (e.g. `Lint`/`Layout`/… `Exclude: \"**/*.yml\"`), otherwise every file of that type will be parsed as Ruby and report `Lint/Syntax` errors."
           }
         }
       }
diff --git a/src/extension.ts b/src/extension.ts
index ebb71b5..2014dfa 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -85,8 +85,12 @@ function getConfig<T> (key: string): T | undefined {
   return workspace.getConfiguration('standardRuby').get<T>(key)
 }
 
+function additionalLanguages (): string[] {
+  return getConfig<string[]>('additionalLanguages') ?? []
+}
+
 function supportedLanguage (languageId: string): boolean {
-  return languageId === 'ruby' || languageId === 'gemfile'
+  return languageId === 'ruby' || languageId === 'gemfile' || additionalLanguages().includes(languageId)
 }
 
 function registerCommands (): Disposable[] {
@@ -267,6 +271,7 @@ function buildLanguageClientOptions (): LanguageClientOptions {
   return {
     documentSelector: [
       { scheme: 'file', language: 'ruby' },
+      ...additionalLanguages().map((language) => ({ scheme: 'file', language })),
       { scheme: 'file', pattern: '**/Gemfile' }
     ],
     diagnosticCollectionName: 'standardRuby',