diff --git a/types/chart.js/chart.js-tests.ts b/types/chart.js/chart.js-tests.ts
index 879ef9bb3f..92607a9917 100644
--- a/types/chart.js/chart.js-tests.ts
+++ b/types/chart.js/chart.js-tests.ts
@@ -59,7 +59,8 @@ const chart: Chart = new Chart(ctx, {
                         borderDash: [5, 15],
                         borderDashOffset: 2,
                         zeroLineBorderDash: [5, 15],
-                        zeroLineBorderDashOffset: 2
+                        zeroLineBorderDashOffset: 2,
+                        lineWidth: [1, 2, 3]
                     }
                 }
             ]
diff --git a/types/chart.js/index.d.ts b/types/chart.js/index.d.ts
index 6becfaba40..706e4641bf 100644
--- a/types/chart.js/index.d.ts
+++ b/types/chart.js/index.d.ts
@@ -412,7 +412,7 @@ declare namespace Chart {
         color?: ChartColor;
         borderDash?: number[];
         borderDashOffset?: number;
-        lineWidth?: number;
+        lineWidth?: number | number[];
         drawBorder?: boolean;
         drawOnChartArea?: boolean;
         drawTicks?: boolean;