diff --git a/types/chart.js/chart.js-tests.ts b/types/chart.js/chart.js-tests.ts
index 6a1bc49819..4f1b48017d 100644
--- a/types/chart.js/chart.js-tests.ts
+++ b/types/chart.js/chart.js-tests.ts
@@ -68,7 +68,21 @@ const chart: Chart = new Chart(ctx, {
             xAxes: [
                 {
                     ticks: {
-                        callback: Math.floor,
+                        callback: (value) => {
+                            if (value === 10) {
+                                return Math.floor(value);
+                            }
+
+                            if (value === 20) {
+                                return `${value}`;
+                            }
+
+                            if (value === 30) {
+                                return undefined;
+                            }
+
+                            return null;
+                        },
                         sampleSize: 10,
                     },
                     gridLines: {
diff --git a/types/chart.js/index.d.ts b/types/chart.js/index.d.ts
index e19f71e7be..7f67fefaa9 100644
--- a/types/chart.js/index.d.ts
+++ b/types/chart.js/index.d.ts
@@ -562,7 +562,10 @@ declare namespace Chart {
         backdropPaddingX?: number;
         backdropPaddingY?: number;
         beginAtZero?: boolean;
-        callback?(value: any, index: any, values: any): string | number;
+        /**
+         * If the callback returns null or undefined the associated grid line will be hidden.
+         */
+        callback?(value: number | string, index: number, values: number[] | string[]): string | number | null | undefined;
         display?: boolean;
         fontColor?: ChartColor;
         fontFamily?: string;