diff --git a/types/index.d.ts b/types/index.d.ts
index 986b1cfec51..435d6bdb489 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -3250,6 +3250,11 @@ export type TimeScaleOptions = Omit<CartesianScaleOptions, 'min' | 'max'> & {
      * @default 'auto'
      */
     source: 'labels' | 'auto' | 'data';
+    /**
+     * The number of units between grid lines.
+     * @default 1
+     */
+    stepSize: number;
   };
 };
 
diff --git a/types/tests/scales/options.ts b/types/tests/scales/options.ts
index 3b545d4e13a..086435b6e7b 100644
--- a/types/tests/scales/options.ts
+++ b/types/tests/scales/options.ts
@@ -17,6 +17,9 @@ const chart = new Chart('test', {
         type: 'time',
         time: {
           unit: 'year'
+        },
+        ticks: {
+          stepSzie: 1
         }
       },
       x1: {