diff --git a/src/Avalonia.Controls/Classes.cs b/src/Avalonia.Controls/Classes.cs
index c897e86697..613273d5c7 100644
--- a/src/Avalonia.Controls/Classes.cs
+++ b/src/Avalonia.Controls/Classes.cs
@@ -179,7 +179,7 @@ namespace Avalonia.Controls
             {
                 ThrowIfPseudoclass(name, "removed");
 
-                if (!Contains(name))
+                if (Contains(name))
                 {
                     c.Add(name);
                 }
diff --git a/tests/Avalonia.Controls.UnitTests/ClassesTests.cs b/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
index c9b9d9f82c..8d2e23d027 100644
--- a/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
@@ -161,5 +161,15 @@ namespace Avalonia.Controls.UnitTests
 
             Assert.Equal(new[] { ":baz" }, target);
         }
+
+        [Fact]
+        public void RemoveAll_Should_Remove_Classes()
+        {
+            var target = new Classes("foo", "bar", "baz");
+
+            target.RemoveAll(new[] { "bar", "baz" });
+
+            Assert.Equal(new[] { "foo" }, target);
+        }
     }
 }