diff --git a/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs b/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
index 569409aa3f..fadcd4b7fa 100644
--- a/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
+++ b/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
@@ -133,6 +133,13 @@ public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activ
         var currentActivity = Activity.Current;
         context.Items[ContextKey] = null;
 
+        // Make sure that the activity has a proper end time before onRequestStoppedCallback is called.
+        // Note that the activity must not be stopped before the callback is called.
+        if (aspNetActivity.Duration == TimeSpan.Zero)
+        {
+            aspNetActivity.SetEndTime(DateTime.UtcNow);
+        }
+
         try
         {
             onRequestStoppedCallback?.Invoke(aspNetActivity, context);
diff --git a/src/OpenTelemetry.Instrumentation.AspNet/CHANGELOG.md b/src/OpenTelemetry.Instrumentation.AspNet/CHANGELOG.md
index ea5d2bd227..a12e1d0aa2 100644
--- a/src/OpenTelemetry.Instrumentation.AspNet/CHANGELOG.md
+++ b/src/OpenTelemetry.Instrumentation.AspNet/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Fixed an issue that caused `http.server.duration` metric value to always be set
+  to `0`. The issue exists in `1.6.0-beta.1` version.
+  ([#1425](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/1425))
+
 ## 1.6.0-beta.1
 
 Released 2023-Oct-11
diff --git a/test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInMetricsListenerTests.cs b/test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInMetricsListenerTests.cs
index cd458aad73..a1cf7c1c24 100644
--- a/test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInMetricsListenerTests.cs
+++ b/test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInMetricsListenerTests.cs
@@ -16,6 +16,7 @@
 
 using System.Collections.Generic;
 using System.IO;
+using System.Threading;
 using System.Web;
 using OpenTelemetry.Context.Propagation;
 using OpenTelemetry.Metrics;
@@ -56,6 +57,7 @@ public void HttpDurationMetricIsEmitted()
             .Build();
 
         var activity = ActivityHelper.StartAspNetActivity(Propagators.DefaultTextMapPropagator, HttpContext.Current, TelemetryHttpModule.Options.OnRequestStartedCallback);
+        Thread.Sleep(1); // Make sure duration is always greater than 0 to avoid flakiness.
         ActivityHelper.StopAspNetActivity(Propagators.DefaultTextMapPropagator, activity, HttpContext.Current, TelemetryHttpModule.Options.OnRequestStoppedCallback);
 
         meterProvider.ForceFlush();
@@ -77,6 +79,7 @@ public void HttpDurationMetricIsEmitted()
         Assert.Equal("http.server.duration", exportedItems[0].Name);
         Assert.Equal(1L, count);
         Assert.Equal(duration, sum);
+        Assert.True(duration > 0, "Metric duration should be set.");
 
         Assert.Equal(3, metricPoints[0].Tags.Count);
         string? httpMethod = null;