diff --git a/packages/experimental-utils/src/ts-eslint/Linter.ts b/packages/experimental-utils/src/ts-eslint/Linter.ts
index 56476834cc03..7449472ce4d9 100644
--- a/packages/experimental-utils/src/ts-eslint/Linter.ts
+++ b/packages/experimental-utils/src/ts-eslint/Linter.ts
@@ -119,6 +119,14 @@ namespace Linter {
   export type RuleEntry = RuleLevel | RuleLevelAndOptions;
   export type RulesRecord = Partial<Record<string, RuleEntry>>;
 
+  export type GlobalVariableOption =
+    | 'readonly'
+    | 'writable'
+    | 'readable'
+    | 'writeable'
+    | 'off'
+    | boolean;
+
   // https://github.com/eslint/eslint/blob/v6.8.0/conf/config-schema.js
   interface BaseConfig {
     $schema?: string;
@@ -133,7 +141,7 @@ namespace Linter {
     /**
      * The global variable settings.
      */
-    globals?: { [name: string]: boolean };
+    globals?: { [name: string]: GlobalVariableOption };
     /**
      * The flag that disables directive comments.
      */