diff --git a/src/Skia/Avalonia.Skia/Gpu/Metal/SkiaMetalGpu.cs b/src/Skia/Avalonia.Skia/Gpu/Metal/SkiaMetalGpu.cs
index 05bcd9fa42..c60b3b3dba 100644
--- a/src/Skia/Avalonia.Skia/Gpu/Metal/SkiaMetalGpu.cs
+++ b/src/Skia/Avalonia.Skia/Gpu/Metal/SkiaMetalGpu.cs
@@ -17,7 +17,7 @@ internal class SkiaMetalGpu : ISkiaGpu
 
     public SkiaMetalGpu(IMetalDevice device, long? maxResourceBytes, bool? useStencilBuffers = null)
     {
-        var avoidStencilBuffers = useStencilBuffers == false;
+        var avoidStencilBuffers = SkiaOptions.ShouldAvoidStencilBuffers(useStencilBuffers);
         _context = GRContext.CreateMetal(
                        new GRMtlBackendContext { DeviceHandle = device.Device, QueueHandle = device.CommandQueue, },
                        new GRContextOptions { AvoidStencilBuffers = avoidStencilBuffers })
diff --git a/src/Skia/Avalonia.Skia/Gpu/OpenGl/GlSkiaGpu.cs b/src/Skia/Avalonia.Skia/Gpu/OpenGl/GlSkiaGpu.cs
index af957551e3..107ab79ac7 100644
--- a/src/Skia/Avalonia.Skia/Gpu/OpenGl/GlSkiaGpu.cs
+++ b/src/Skia/Avalonia.Skia/Gpu/OpenGl/GlSkiaGpu.cs
@@ -40,7 +40,7 @@ namespace Avalonia.Skia
                 
                 using(iface)
                 {
-                    var avoidStencilBuffers = useStencilBuffers == false;
+                    var avoidStencilBuffers = SkiaOptions.ShouldAvoidStencilBuffers(useStencilBuffers);
                     _grContext = GRContext.CreateGl(iface, new GRContextOptions { AvoidStencilBuffers = avoidStencilBuffers });
                     if (maxResourceBytes.HasValue)
                     {
diff --git a/src/Skia/Avalonia.Skia/Gpu/Vulkan/VulkanSkiaGpu.cs b/src/Skia/Avalonia.Skia/Gpu/Vulkan/VulkanSkiaGpu.cs
index b66054b340..9f8a746044 100644
--- a/src/Skia/Avalonia.Skia/Gpu/Vulkan/VulkanSkiaGpu.cs
+++ b/src/Skia/Avalonia.Skia/Gpu/Vulkan/VulkanSkiaGpu.cs
@@ -48,7 +48,7 @@ internal class VulkanSkiaGpu : ISkiaGpu
                 GetProcedureAddress = GetProcAddressWrapper
             };
 
-            var avoidStencilBuffers = useStencilBuffers == false;
+            var avoidStencilBuffers = SkiaOptions.ShouldAvoidStencilBuffers(useStencilBuffers);
             
             GrContext = GRContext.CreateVulkan(ctx, new GRContextOptions { AvoidStencilBuffers = avoidStencilBuffers }) ??
                          throw new VulkanException("Unable to create GrContext from IVulkanDevice");
diff --git a/src/Skia/Avalonia.Skia/SkiaOptions.cs b/src/Skia/Avalonia.Skia/SkiaOptions.cs
index 1a95919300..9afaf6b307 100644
--- a/src/Skia/Avalonia.Skia/SkiaOptions.cs
+++ b/src/Skia/Avalonia.Skia/SkiaOptions.cs
@@ -26,9 +26,17 @@ namespace Avalonia
         public bool UseOpacitySaveLayer { get; set; } = false;
         
         /// <summary>
-        /// Gets whether stencil buffers can be used for various draw operations, improving performance.
-        /// If null (the default), Avalonia chooses whether to enable stencil buffers depending on the platform.
+        /// Gets whether stencil buffers can be used for various draw operations, improving clipping performance.
+        /// Enabling them lets Skia pick multisample-based path rendering, which quantizes edge coverage and
+        /// visibly degrades anti-aliasing of vector geometry, so they are disabled unless explicitly requested.
         /// </summary>
         public bool? UseStencilBuffers { get; set; }
+
+        /// <summary>
+        /// Maps <see cref="UseStencilBuffers"/> onto Skia's inverted <c>GRContextOptions.AvoidStencilBuffers</c>.
+        /// Only an explicit <c>true</c> opts in: stencil buffers trade geometry anti-aliasing quality for
+        /// clipping speed (see issue #21760), so they must never be enabled implicitly.
+        /// </summary>
+        internal static bool ShouldAvoidStencilBuffers(bool? useStencilBuffers) => useStencilBuffers != true;
     }
 }
diff --git a/tests/Avalonia.Skia.UnitTests/SkiaOptionsTests.cs b/tests/Avalonia.Skia.UnitTests/SkiaOptionsTests.cs
new file mode 100644
index 0000000000..660d89b929
--- /dev/null
+++ b/tests/Avalonia.Skia.UnitTests/SkiaOptionsTests.cs
@@ -0,0 +1,19 @@
+using Xunit;
+
+namespace Avalonia.Skia.UnitTests
+{
+    public class SkiaOptionsTests
+    {
+        // Stencil buffers let Skia choose multisample-based path rendering, which quantizes edge
+        // coverage and visibly degraded vector geometry anti-aliasing on GPU backends in 12.1.0.
+        // They are a performance opt-in, so anything other than an explicit `true` must avoid them.
+        [Theory]
+        [InlineData(null, true)]
+        [InlineData(false, true)]
+        [InlineData(true, false)]
+        public void Stencil_Buffers_Are_Avoided_Unless_Explicitly_Enabled(bool? useStencilBuffers, bool expected)
+        {
+            Assert.Equal(expected, SkiaOptions.ShouldAvoidStencilBuffers(useStencilBuffers));
+        }
+    }
+}