diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
index 1e8aa8942b7953..c2f6a196b48522 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
@@ -7,6 +7,7 @@
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Temporal/Duration.h>
 #include <LibJS/Runtime/Temporal/DurationPrototype.h>
+#include <math.h>
 
 namespace JS::Temporal {
 
@@ -41,6 +42,7 @@ void DurationPrototype::initialize(GlobalObject& global_object)
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_native_function(vm.names.with, with, 1, attr);
     define_native_function(vm.names.negated, negated, 0, attr);
+    define_native_function(vm.names.abs, abs, 0, attr);
     define_native_function(vm.names.valueOf, value_of, 0, attr);
 }
 
@@ -311,6 +313,19 @@ JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::negated)
     return create_temporal_duration(global_object, -duration->years(), -duration->months(), -duration->weeks(), -duration->days(), -duration->hours(), -duration->minutes(), -duration->seconds(), -duration->milliseconds(), -duration->microseconds(), -duration->nanoseconds());
 }
 
+// 7.3.17 Temporal.Duration.prototype.abs ( ), https://tc39.es/proposal-temporal/#sec-temporal.duration.prototype.abs
+JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::abs)
+{
+    // 1. Let duration be the this value.
+    // 2. Perform ? RequireInternalSlot(duration, [[InitializedTemporalDuration]]).
+    auto* duration = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Return ? CreateTemporalDuration(abs(duration.[[Years]]), abs(duration.[[Months]]), abs(duration.[[Weeks]]), abs(duration.[[Days]]), abs(duration.[[Hours]]), abs(duration.[[Minutes]]), abs(duration.[[Seconds]]), abs(duration.[[Milliseconds]]), abs(duration.[[Microseconds]]), abs(duration.[[Nanoseconds]])).
+    return create_temporal_duration(global_object, fabs(duration->years()), fabs(duration->months()), fabs(duration->weeks()), fabs(duration->days()), fabs(duration->hours()), fabs(duration->minutes()), fabs(duration->seconds()), fabs(duration->milliseconds()), fabs(duration->microseconds()), fabs(duration->nanoseconds()));
+}
+
 // 7.3.25 Temporal.Duration.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.duration.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::value_of)
 {
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
index 7d57107905b226..5d06103a5e1d7d 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
@@ -33,6 +33,7 @@ class DurationPrototype final : public Object {
     JS_DECLARE_NATIVE_FUNCTION(blank_getter);
     JS_DECLARE_NATIVE_FUNCTION(with);
     JS_DECLARE_NATIVE_FUNCTION(negated);
+    JS_DECLARE_NATIVE_FUNCTION(abs);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
 };
 
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.abs.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.abs.js
new file mode 100644
index 00000000000000..d5e6b6b840f91c
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.abs.js
@@ -0,0 +1,53 @@
+const DURATION_PROPERTIES = [
+    "years",
+    "months",
+    "weeks",
+    "days",
+    "hours",
+    "minutes",
+    "seconds",
+    "milliseconds",
+    "microseconds",
+    "nanoseconds",
+];
+
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Duration.prototype.abs).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        let absoluteDuration;
+
+        absoluteDuration = new Temporal.Duration(123).abs();
+        expect(absoluteDuration.years).toBe(123);
+
+        absoluteDuration = new Temporal.Duration(-123).abs();
+        expect(absoluteDuration.years).toBe(123);
+    });
+
+    test("each property is made absolute", () => {
+        let values;
+        let duration;
+
+        values = Array(DURATION_PROPERTIES.length).fill(-1);
+        duration = new Temporal.Duration(...values).abs();
+        for (const property of DURATION_PROPERTIES) {
+            expect(duration[property]).toBe(1);
+        }
+
+        values = Array(DURATION_PROPERTIES.length).fill(1);
+        duration = new Temporal.Duration(...values).abs();
+        for (const property of DURATION_PROPERTIES) {
+            expect(duration[property]).toBe(1);
+        }
+    });
+});
+
+test("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Temporal.Duration.prototype.abs.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Duration");
+    });
+});