diff --git a/src/AvaloniaMath/Fonts/AvaloniaSystemFont.cs b/src/AvaloniaMath/Fonts/AvaloniaSystemFont.cs
index 6cb8c3d2..38e88893 100644
--- a/src/AvaloniaMath/Fonts/AvaloniaSystemFont.cs
+++ b/src/AvaloniaMath/Fonts/AvaloniaSystemFont.cs
@@ -7,7 +7,7 @@
 
 namespace AvaloniaMath.Fonts;
 
-internal class AvaloniaSystemFont : ITeXFont
+internal sealed class AvaloniaSystemFont : ITeXFont
 {
     private readonly string _fontFamily;
 
diff --git a/src/AvaloniaMath/Rendering/AvaloniaElementRenderer.cs b/src/AvaloniaMath/Rendering/AvaloniaElementRenderer.cs
index 720b0225..beff7c73 100644
--- a/src/AvaloniaMath/Rendering/AvaloniaElementRenderer.cs
+++ b/src/AvaloniaMath/Rendering/AvaloniaElementRenderer.cs
@@ -15,7 +15,7 @@
 namespace AvaloniaMath.Rendering;
 
 /// <summary>The renderer that uses Avalonia drawing context.</summary>
-internal class AvaloniaElementRenderer : IElementRenderer
+internal sealed class AvaloniaElementRenderer : IElementRenderer
 {
     private readonly DrawingContext _foregroundContext;
     private readonly double _scale;
@@ -94,10 +94,10 @@ private static Transform ToTransform(Transformation transformation)
         switch (transformation.Kind)
         {
             case TransformationKind.Translate:
-                var tt = (Transformation.Translate) transformation;
+                var tt = (Transformation.Translate)transformation;
                 return new TranslateTransform(tt.X, tt.Y);
             case TransformationKind.Rotate:
-                var rt = (Transformation.Rotate) transformation;
+                var rt = (Transformation.Rotate)transformation;
                 return new RotateTransform(rt.RotationDegrees);
             default:
                 throw new NotSupportedException($"Unknown {nameof(Transformation)} kind: {transformation.Kind}");
diff --git a/src/AvaloniaMath/Rendering/GeometryElementRenderer.cs b/src/AvaloniaMath/Rendering/GeometryElementRenderer.cs
index 63355f5b..06fdf5f0 100644
--- a/src/AvaloniaMath/Rendering/GeometryElementRenderer.cs
+++ b/src/AvaloniaMath/Rendering/GeometryElementRenderer.cs
@@ -11,7 +11,7 @@ namespace AvaloniaMath.Rendering;
 
 /// <summary>A renderer that renders the elements to a provided <see cref="GeometryGroup"/> instance.</summary>
 // TODO[#357]: Make this work
-internal class GeometryElementRenderer : IElementRenderer
+internal sealed class GeometryElementRenderer : IElementRenderer
 {
     private readonly GeometryGroup _geometry;
     private readonly double _scale;
diff --git a/src/XamlMath.Shared/Build/IsExternalInit.cs b/src/XamlMath.Shared/Build/IsExternalInit.cs
index 5298a49a..7795b71a 100644
--- a/src/XamlMath.Shared/Build/IsExternalInit.cs
+++ b/src/XamlMath.Shared/Build/IsExternalInit.cs
@@ -3,7 +3,7 @@ namespace System.Runtime.CompilerServices;
 
 #if !NET5_0_OR_GREATER
 /// <summary>This is only used to enable init-only attributes for older target frameworks.</summary>
-internal class IsExternalInit
+internal sealed class IsExternalInit
 {
 }
 #endif
diff --git a/src/XamlMath.Shared/DelimiterInfo.cs b/src/XamlMath.Shared/DelimiterInfo.cs
index 62d103fe..65d96d17 100644
--- a/src/XamlMath.Shared/DelimiterInfo.cs
+++ b/src/XamlMath.Shared/DelimiterInfo.cs
@@ -5,7 +5,7 @@ namespace XamlMath;
 /// <summary>
 /// Information about the body between a pair of delimiters.
 /// </summary>
-internal class DelimiterInfo
+internal sealed class DelimiterInfo
 {
     public Atom Body { get; }
 
diff --git a/src/XamlMath.Shared/TexFormulaHelper.cs b/src/XamlMath.Shared/TexFormulaHelper.cs
index 16a42eab..37c9cd33 100644
--- a/src/XamlMath.Shared/TexFormulaHelper.cs
+++ b/src/XamlMath.Shared/TexFormulaHelper.cs
@@ -6,7 +6,7 @@
 
 namespace XamlMath;
 
-internal class TexFormulaHelper
+internal sealed class TexFormulaHelper
 {
     private readonly TexFormulaParser _formulaParser;
     private readonly SourceSpan _source;