diff --git a/packages/proto-loader/src/index.ts b/packages/proto-loader/src/index.ts
index a3554f75..2e1a2b84 100644
--- a/packages/proto-loader/src/index.ts
+++ b/packages/proto-loader/src/index.ts
@@ -285,7 +285,7 @@ export function loadSync(filename: string, options?: Options): PackageDefinition
   options = options || {};
   if (!!options.includeDirs) {
     if (!(Array.isArray(options.includeDirs))) {
-      throw new Error('The include option must be an array');
+      throw new Error('The includeDirs option must be an array');
     }
     addIncludePathResolver(root, options.includeDirs as string[]);
   }