diff --git a/types/relay-runtime/index.d.ts b/types/relay-runtime/index.d.ts
index 2ec05e85a3..f9b78fad7e 100644
--- a/types/relay-runtime/index.d.ts
+++ b/types/relay-runtime/index.d.ts
@@ -700,6 +700,7 @@ interface ReaderLiteral {
 interface ReaderVariable {
     readonly kind: string; // 'Variable';
     readonly name: string;
+    readonly type?: string | null;
     readonly variableName: string;
 }