diff --git a/samples/ControlCatalog/Pages/TextBoxPage.xaml b/samples/ControlCatalog/Pages/TextBoxPage.xaml
index 346e561dfc..5c885ad091 100644
--- a/samples/ControlCatalog/Pages/TextBoxPage.xaml
+++ b/samples/ControlCatalog/Pages/TextBoxPage.xaml
@@ -96,6 +96,12 @@
         <TextBox Width="200" Text="Custom font italic" FontWeight="Normal" FontStyle="Italic" FontFamily="/Assets/Fonts/SourceSansPro-Italic.ttf#Source Sans Pro"/>
         <TextBox Width="200" Text="Custom font italic bold" FontWeight="Bold" FontStyle="Italic" FontFamily="/Assets/Fonts/SourceSansPro-*.ttf#Source Sans Pro"/>
       </StackPanel>
+
+      <StackPanel Orientation="Vertical" Spacing="8" Margin="8">
+        <TextBox Width="200" Text="Default casing" />
+        <TextBox Width="200" Text="Upper casing" CharacterCasing="Upper" />
+        <TextBox Width="200" Text="Lower casing" CharacterCasing="Lower" />
+      </StackPanel>
     </WrapPanel>
     <TextBox AcceptsReturn="True" TextWrapping="Wrap" Height="200" MaxWidth="400"
              FontFamily="avares://ControlCatalog/Assets/Fonts#WenQuanYi Micro Hei"
diff --git a/src/Avalonia.Base/Media/CharacterCasing.cs b/src/Avalonia.Base/Media/CharacterCasing.cs
new file mode 100644
index 0000000000..2cb30cacb9
--- /dev/null
+++ b/src/Avalonia.Base/Media/CharacterCasing.cs
@@ -0,0 +1,23 @@
+namespace Avalonia.Media
+{
+    /// <summary>
+    /// Defines how text is cased.
+    /// </summary>
+    public enum CharacterCasing
+    {
+        /// <summary>
+        /// The text casing is normal.
+        /// </summary>
+        Normal,
+
+        /// <summary>
+        /// The text casing is upper.
+        /// </summary>
+        Upper,
+
+        /// <summary>
+        /// The text casing is lower.
+        /// </summary>
+        Lower
+    }
+}
diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index eadb54b58a..7a93a813bc 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -159,6 +159,9 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<TextAlignment> TextAlignmentProperty =
             TextBlock.TextAlignmentProperty.AddOwner<TextBox>();
 
+        public static readonly StyledProperty<CharacterCasing> CharacterCasingProperty =
+            AvaloniaProperty.Register<TextBox, CharacterCasing>(nameof(CharacterCasing), defaultValue: CharacterCasing.Normal);
+
         /// <summary>
         /// Defines the <see cref="HorizontalAlignment"/> property.
         /// </summary>
@@ -455,6 +458,14 @@ namespace Avalonia.Controls
             set => SetValue(CaretIndexProperty, value);
         }
 
+        private void OnCharacterCasingChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            var tb = (TextBox)e.Sender;
+            var newValue = AdjustCasing(tb.Text, e.GetNewValue<CharacterCasing>());
+
+            SetCurrentValue(TextProperty, newValue);
+        }
+
         private void OnCaretIndexChanged(AvaloniaPropertyChangedEventArgs e)
         {
             UndoRedoState state;
@@ -638,8 +649,8 @@ namespace Avalonia.Controls
             {
                 SnapshotUndoRedo();
             }
-
-            return value;
+            
+            return AdjustCasing(value, textBox.CharacterCasing);
         }
 
         /// <summary>
@@ -691,6 +702,15 @@ namespace Avalonia.Controls
             set => SetValue(TextAlignmentProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="CharacterCasing"/> of the TextBox.
+        /// </summary>
+        public CharacterCasing CharacterCasing
+        {
+            get => GetValue(CharacterCasingProperty);
+            set => SetValue(CharacterCasingProperty, value);
+        }
+
         /// <summary>
         /// Gets or sets the placeholder or descriptive text that is displayed even if the <see cref="Text"/>
         /// property is not yet set.
@@ -1036,12 +1056,15 @@ namespace Avalonia.Controls
                 CoerceValue(CaretIndexProperty);
                 CoerceValue(SelectionStartProperty);
                 CoerceValue(SelectionEndProperty);
-
                 RaiseTextChangeEvents();
 
                 UpdatePseudoclasses();
                 UpdateCommandStates();
             }
+            else if (change.Property == CharacterCasingProperty)
+            {
+                OnCharacterCasingChanged(change);
+            }
             else if (change.Property == CaretIndexProperty)
             {
                 OnCaretIndexChanged(change);
@@ -1158,6 +1181,7 @@ namespace Avalonia.Controls
             }
 
             input = SanitizeInputText(input);
+            input = AdjustCasing(input, CharacterCasing);
 
             if (string.IsNullOrEmpty(input))
             {
@@ -2272,6 +2296,20 @@ namespace Avalonia.Controls
             return text.Substring(start, end - start);
         }
 
+        /// <summary>
+        /// Adjust the text casing.
+        /// </summary>
+        /// <param name="text">The text to adjust.</param>
+        /// <param name="characterCasing">The character casing we want.</param>
+        /// <returns></returns>
+        private static string? AdjustCasing(string? text, CharacterCasing characterCasing) => characterCasing switch
+        {
+            CharacterCasing.Lower => text?.ToLower(System.Globalization.CultureInfo.CurrentCulture),
+            CharacterCasing.Upper => text?.ToUpper(System.Globalization.CultureInfo.CurrentCulture),
+            CharacterCasing.Normal => text,
+            _ => text
+        };
+
         /// <summary>
         /// Returns the sum of any vertical whitespace added between the <see cref="ScrollViewer"/> and <see cref="TextPresenter"/> in the control template.
         /// </summary>
diff --git a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
index fa578a7afe..a83b2c8b61 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
@@ -1517,6 +1517,37 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Theory]
+        [InlineData(CharacterCasing.Lower, "LoWer", "lower")]
+        [InlineData(CharacterCasing.Upper, "uppEr", "UPPER")]
+        [InlineData(CharacterCasing.Normal, "NorMal", "NorMal")]
+        public void Should_Respect_Casing(CharacterCasing casing, string value, string expected)
+        {
+            var target = new TextBox
+            {
+                Template = CreateTemplate(),
+                CharacterCasing = casing,
+                Text = value
+            };
+
+            Assert.Equal(target.Text, expected);
+        }
+
+        [Fact]
+        public void Should_Update_Casing_After_First_Render()
+        {
+            var tb = new TextBox
+            {
+                Template = CreateTemplate(),
+                Text = "abc"
+            };
+
+            tb.Measure(Size.Infinity);
+            tb.CharacterCasing = CharacterCasing.Upper;
+            
+            Assert.Equal("ABC", tb.Text);
+        }
+
         [Fact]
         public void Should_Move_Caret_To_EndOfLine()
         {