diff --git a/Test/UnitTests/EventTriggerTests.cs b/Test/UnitTests/EventTriggerTests.cs
index 369e6ec..c021233 100644
--- a/Test/UnitTests/EventTriggerTests.cs
+++ b/Test/UnitTests/EventTriggerTests.cs
@@ -16,9 +16,9 @@ public class EventTriggerTest
 
         [TestInitialize]
         public void Setup()
-            {
-                Interaction.ShouldRunInDesignMode = true;
-            }
+        {
+            Interaction.ShouldRunInDesignMode = true;
+        }
 
         [TestCleanup]
         public void Teardown()
diff --git a/Test/UnitTests/KeyTriggerTest.cs b/Test/UnitTests/KeyTriggerTest.cs
new file mode 100644
index 0000000..d754912
--- /dev/null
+++ b/Test/UnitTests/KeyTriggerTest.cs
@@ -0,0 +1,181 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Microsoft.Xaml.Behaviors;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows;
+using Microsoft.Xaml.Behaviors.Input;
+using System.Windows.Interop;
+using System;
+
+namespace Microsoft.Xaml.Interactions.UnitTests
+{
+    [TestClass]
+    public class KeyTriggerTest
+    {
+        #region Setup/teardown
+
+        [TestInitialize]
+        public void Setup()
+        {
+            Interaction.ShouldRunInDesignMode = true;
+        }
+
+        [TestCleanup]
+        public void Teardown()
+        {
+            Interaction.ShouldRunInDesignMode = false;
+        }
+
+        #endregion
+
+        #region Test methods
+
+        [TestMethod]
+        [DataRow(Key.A)]
+        [DataRow(Key.B)]
+        [DataRow(Key.C)]
+        [DataRow(Key.D)]
+        [DataRow(Key.E)]
+        [DataRow(Key.F)]
+        [DataRow(Key.G)]
+        [DataRow(Key.H)]
+        [DataRow(Key.I)]
+        [DataRow(Key.J)]
+        [DataRow(Key.K)]
+        [DataRow(Key.L)]
+        [DataRow(Key.M)]
+        [DataRow(Key.N)]
+        [DataRow(Key.O)]
+        [DataRow(Key.P)]
+        [DataRow(Key.Q)]
+        [DataRow(Key.R)]
+        [DataRow(Key.S)]
+        [DataRow(Key.T)]
+        [DataRow(Key.U)]
+        [DataRow(Key.V)]
+        [DataRow(Key.W)]
+        [DataRow(Key.X)]
+        [DataRow(Key.Y)]
+        [DataRow(Key.Z)]
+        [DataRow(Key.NumPad1)]
+        [DataRow(Key.NumPad2)]
+        [DataRow(Key.NumPad3)]
+        [DataRow(Key.NumPad4)]
+        [DataRow(Key.NumPad5)]
+        [DataRow(Key.NumPad6)]
+        [DataRow(Key.NumPad7)]
+        [DataRow(Key.NumPad8)]
+        [DataRow(Key.NumPad9)]
+        [DataRow(Key.Enter)]
+        [DataRow(Key.Tab)]
+        public void KeyTrigger_InvokesActions_WhenKeyIsPressed(Key key)
+        {
+            var textBox = new TextBox();
+            var keyTrigger = new KeyTrigger { Key = key };
+            var action = new StubAction();
+            keyTrigger.Actions.Add(action);
+            keyTrigger.Attach(textBox);
+
+            Grid grid = new Grid();
+            grid.Children.Add(textBox);
+            using (StubWindow window = new StubWindow(grid))
+            {
+                var inputSource = PresentationSource.FromVisual(textBox) ?? new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero);
+                var keyEventArgs = new KeyEventArgs(Keyboard.PrimaryDevice, inputSource, 0, key);
+                keyEventArgs.RoutedEvent = Keyboard.KeyDownEvent;
+                textBox.RaiseEvent(keyEventArgs);
+
+                Assert.AreEqual(1, action.InvokeCount);
+            }
+        }
+
+        [TestMethod]
+        [DataRow(Key.A)]
+        [DataRow(Key.B)]
+        [DataRow(Key.C)]
+        [DataRow(Key.D)]
+        [DataRow(Key.E)]
+        [DataRow(Key.F)]
+        [DataRow(Key.G)]
+        [DataRow(Key.H)]
+        [DataRow(Key.I)]
+        [DataRow(Key.J)]
+        [DataRow(Key.K)]
+        [DataRow(Key.L)]
+        [DataRow(Key.M)]
+        [DataRow(Key.N)]
+        [DataRow(Key.O)]
+        [DataRow(Key.P)]
+        [DataRow(Key.Q)]
+        [DataRow(Key.R)]
+        [DataRow(Key.S)]
+        [DataRow(Key.T)]
+        [DataRow(Key.U)]
+        [DataRow(Key.V)]
+        [DataRow(Key.W)]
+        [DataRow(Key.X)]
+        [DataRow(Key.Y)]
+        [DataRow(Key.Z)]
+        [DataRow(Key.NumPad1)]
+        [DataRow(Key.NumPad2)]
+        [DataRow(Key.NumPad3)]
+        [DataRow(Key.NumPad4)]
+        [DataRow(Key.NumPad5)]
+        [DataRow(Key.NumPad6)]
+        [DataRow(Key.NumPad7)]
+        [DataRow(Key.NumPad8)]
+        [DataRow(Key.NumPad9)]
+        [DataRow(Key.Enter)]
+        [DataRow(Key.Tab)]
+        public void KeyTrigger_InvokesActions_WhenKeyIsReleased(Key key)
+        {
+            var textBox = new TextBox();
+            var keyTrigger = new KeyTrigger { Key = key, FiredOn = KeyTriggerFiredOn.KeyUp };
+            var action = new StubAction();
+            keyTrigger.Actions.Add(action);
+            keyTrigger.Attach(textBox);
+
+            Grid grid = new Grid();
+            grid.Children.Add(textBox);
+            using (StubWindow window = new StubWindow(grid))
+            {
+                var inputSource = PresentationSource.FromVisual(textBox) ?? new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero);
+                var keyEventArgs = new KeyEventArgs(Keyboard.PrimaryDevice, inputSource, 0, key);
+                keyEventArgs.RoutedEvent = Keyboard.KeyUpEvent;
+                textBox.RaiseEvent(keyEventArgs);
+
+                Assert.AreEqual(1, action.InvokeCount);
+            }
+        }
+
+
+        [TestMethod]
+        [DataRow(true)]
+        [DataRow(false)]
+        public void KeyTrigger_InvokesActionsOnce_WhenLoadedEventFiredMultipleTimes(bool activeOnFocus)
+        {
+            var textBox = new TextBox();
+            var keyTrigger = new KeyTrigger { ActiveOnFocus = activeOnFocus, Key = Key.Enter };
+            var action = new StubAction();
+            keyTrigger.Actions.Add(action);
+            keyTrigger.Attach(textBox);
+
+            Grid grid = new Grid();
+            grid.Children.Add(textBox);
+            using (StubWindow window = new StubWindow(grid))
+            {
+                //simulate the loaded event being invoked multiple times; for example, when using an element in a tab control
+                textBox.RaiseEvent(new RoutedEventArgs(FrameworkElement.LoadedEvent));
+
+                var inputSource = PresentationSource.FromVisual(textBox) ?? new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero);
+                var keyEventArgs = new KeyEventArgs(Keyboard.PrimaryDevice, inputSource, 0, Key.Enter);
+                keyEventArgs.RoutedEvent = Keyboard.KeyDownEvent;
+                textBox.RaiseEvent(keyEventArgs);
+
+                Assert.AreEqual(1, action.InvokeCount);
+            }
+        }
+
+        #endregion
+    }
+}
diff --git a/src/Microsoft.Xaml.Behaviors/EventTriggerBase.cs b/src/Microsoft.Xaml.Behaviors/EventTriggerBase.cs
index d62cad0..bfeff3a 100644
--- a/src/Microsoft.Xaml.Behaviors/EventTriggerBase.cs
+++ b/src/Microsoft.Xaml.Behaviors/EventTriggerBase.cs
@@ -408,7 +408,11 @@ private void RegisterLoaded(FrameworkElement associatedElement)
             }
         }
 
-        private void UnregisterLoaded(FrameworkElement associatedElement)
+        /// <summary>
+        /// Removes the event handler from the Loaded event of the associated object.
+        /// </summary>
+        /// <param name="associatedElement">The associated object</param>
+        protected void UnregisterLoaded(FrameworkElement associatedElement)
         {
             Debug.Assert(this.eventHandlerMethodInfo == null);
             if (this.IsLoadedRegistered && associatedElement != null)
diff --git a/src/Microsoft.Xaml.Behaviors/Input/KeyTrigger.cs b/src/Microsoft.Xaml.Behaviors/Input/KeyTrigger.cs
index 1ddf228..aece7b3 100644
--- a/src/Microsoft.Xaml.Behaviors/Input/KeyTrigger.cs
+++ b/src/Microsoft.Xaml.Behaviors/Input/KeyTrigger.cs
@@ -117,6 +117,10 @@ protected override void OnEvent(EventArgs eventArgs)
             {
                 this.targetElement.KeyUp += this.OnKeyPress;
             }
+
+            // Unregister the Loaded event of the Source object to prevent the KeyUp or KeyDown events from being registered multiple times.
+            // this is especially important when the KeyTrigger is used in a TabControl/TabItem.
+            UnregisterLoaded(Source as FrameworkElement);
         }
 
         protected override void OnDetaching()