diff --git a/polyfill/index.d.ts b/polyfill/index.d.ts
index 7d4f5ff55..5bd1637c6 100644
--- a/polyfill/index.d.ts
+++ b/polyfill/index.d.ts
@@ -507,6 +507,36 @@ export namespace Temporal {
     nanoseconds?: number;
   };
 
+  /**
+   * Options for Intl.DurationFormat
+   */
+  export type DurationFormatOptions = {
+    localeMatcher?: 'lookup' | 'best fit' | undefined;
+    numberingSystem?: string | undefined;
+    style?: 'long' | 'short' | 'narrow' | 'digital' | undefined;
+    years?: 'long' | 'short' | 'narrow' | undefined;
+    yearsDisplay?: 'always' | 'auto' | undefined;
+    months?: 'long' | 'short' | 'narrow' | undefined;
+    monthsDisplay?: 'always' | 'auto' | undefined;
+    weeks?: 'long' | 'short' | 'narrow' | undefined;
+    weeksDisplay?: 'always' | 'auto' | undefined;
+    days?: 'long' | 'short' | 'narrow' | undefined;
+    daysDisplay?: 'always' | 'auto' | undefined;
+    hours?: 'long' | 'short' | 'narrow' | 'numeric' | '2-digit' | undefined;
+    hoursDisplay?: 'always' | 'auto' | undefined;
+    minutes?: 'long' | 'short' | 'narrow' | 'numeric' | '2-digit' | undefined;
+    minutesDisplay?: 'always' | 'auto' | undefined;
+    seconds?: 'long' | 'short' | 'narrow' | 'numeric' | '2-digit' | undefined;
+    secondsDisplay?: 'always' | 'auto' | undefined;
+    milliseconds?: 'long' | 'short' | 'narrow' | 'numeric' | undefined;
+    millisecondsDisplay?: 'always' | 'auto' | undefined;
+    microseconds?: 'long' | 'short' | 'narrow' | 'numeric' | undefined;
+    microsecondsDisplay?: 'always' | 'auto' | undefined;
+    nanoseconds?: 'long' | 'short' | 'narrow' | 'numeric' | undefined;
+    nanosecondsDisplay?: 'always' | 'auto' | undefined;
+    fractionalDigits?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | undefined;
+  };
+
   /**
    *
    * A `Temporal.Duration` represents an immutable duration of time which can be
@@ -552,7 +582,7 @@ export namespace Temporal {
     subtract(other: Temporal.Duration | DurationLike | string): Temporal.Duration;
     round(roundTo: DurationRoundTo): Temporal.Duration;
     total(totalOf: DurationTotalOf): number;
-    toLocaleString(locales?: globalThis.Intl.LocalesArgument, options?: globalThis.Intl.DateTimeFormatOptions): string;
+    toLocaleString(locales?: globalThis.Intl.LocalesArgument, options?: DurationFormatOptions): string;
     toJSON(): string;
     toString(options?: ToStringPrecisionOptions): string;
     valueOf(): never;