diff --git a/types/truncate-middle/index.d.ts b/types/truncate-middle/index.d.ts
index ec4f3e52e7..9758d4435c 100644
--- a/types/truncate-middle/index.d.ts
+++ b/types/truncate-middle/index.d.ts
@@ -3,6 +3,6 @@
 // Definitions by: Gary King <https://github.com/garyking>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-declare function truncateMiddle(text: string, frontLength?: number, backLength?: number, ellipsis?: string): string;
+declare function truncateMiddle(text: string | null, frontLength?: number, backLength?: number, ellipsis?: string): string;
 
 export = truncateMiddle;
diff --git a/types/truncate-middle/truncate-middle-tests.ts b/types/truncate-middle/truncate-middle-tests.ts
index 9bb60ee7d1..eb1b28a776 100644
--- a/types/truncate-middle/truncate-middle-tests.ts
+++ b/types/truncate-middle/truncate-middle-tests.ts
@@ -7,3 +7,5 @@ truncateMiddle('text', 1);
 truncateMiddle('text', 1, 2);
 
 truncateMiddle('text', 1, 2, '...');
+
+truncateMiddle(null);