diff --git a/src/Avalonia.Base/Media/FontManager.cs b/src/Avalonia.Base/Media/FontManager.cs
index 595a2f3474..1c051e19e7 100644
--- a/src/Avalonia.Base/Media/FontManager.cs
+++ b/src/Avalonia.Base/Media/FontManager.cs
@@ -119,7 +119,9 @@ namespace Avalonia.Media
                     }
                 }
 
-                if (fontCollection != null && fontCollection.TryGetGlyphTypeface(fontFamily.FamilyNames.PrimaryFamilyName,
+                var familyName = fontFamily.FamilyNames.PrimaryFamilyName.ToUpperInvariant();
+
+                if (fontCollection != null && fontCollection.TryGetGlyphTypeface(familyName,
                     typeface.Style, typeface.Weight, typeface.Stretch, out glyphTypeface))
                 {
                     return true;
@@ -133,13 +135,13 @@ namespace Avalonia.Media
 
             foreach (var familyName in fontFamily.FamilyNames)
             {
-                if (SystemFonts.TryGetGlyphTypeface(familyName, typeface.Style, typeface.Weight, typeface.Stretch, out glyphTypeface))
+                if (SystemFonts.TryGetGlyphTypeface(familyName.ToUpperInvariant(), typeface.Style, typeface.Weight, typeface.Stretch, out glyphTypeface))
                 {
                     return true;
                 }
             }
 
-            return SystemFonts.TryGetGlyphTypeface(DefaultFontFamilyName, typeface.Style, typeface.Weight, typeface.Stretch, out glyphTypeface);
+            return SystemFonts.TryGetGlyphTypeface(DefaultFontFamilyName.ToUpperInvariant(), typeface.Style, typeface.Weight, typeface.Stretch, out glyphTypeface);
         }
 
         /// <summary>
diff --git a/src/Avalonia.Base/Media/Fonts/EmbeddedFontCollection.cs b/src/Avalonia.Base/Media/Fonts/EmbeddedFontCollection.cs
index f2fb490592..3350358d68 100644
--- a/src/Avalonia.Base/Media/Fonts/EmbeddedFontCollection.cs
+++ b/src/Avalonia.Base/Media/Fonts/EmbeddedFontCollection.cs
@@ -3,7 +3,6 @@ using System.Collections;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Globalization;
 using Avalonia.Platform;
 
 namespace Avalonia.Media.Fonts
@@ -43,11 +42,13 @@ namespace Avalonia.Media.Fonts
 
                 if (fontManager.TryCreateGlyphTypeface(stream, out var glyphTypeface))
                 {
-                    if (!_glyphTypefaceCache.TryGetValue(glyphTypeface.FamilyName, out var glyphTypefaces))
+                    var familyName = glyphTypeface.FamilyName.ToUpperInvariant();
+
+                    if (!_glyphTypefaceCache.TryGetValue(familyName, out var glyphTypefaces))
                     {
                         glyphTypefaces = new ConcurrentDictionary<FontCollectionKey, IGlyphTypeface>();
 
-                        if (_glyphTypefaceCache.TryAdd(glyphTypeface.FamilyName, glyphTypefaces))
+                        if (_glyphTypefaceCache.TryAdd(familyName, glyphTypefaces))
                         {
                             _fontFamilies.Add(new FontFamily(_key, glyphTypeface.FamilyName));
                         }
@@ -86,6 +87,8 @@ namespace Avalonia.Media.Fonts
         public bool TryGetGlyphTypeface(string familyName, FontStyle style, FontWeight weight,
             FontStretch stretch, [NotNullWhen(true)] out IGlyphTypeface? glyphTypeface)
         {
+            familyName = familyName.ToUpperInvariant();
+
             var key = new FontCollectionKey(style, weight, stretch);
 
             if (_glyphTypefaceCache.TryGetValue(familyName, out var glyphTypefaces))
@@ -101,9 +104,11 @@ namespace Avalonia.Media.Fonts
             {
                 var fontFamily = _fontFamilies[i];
 
-                if (fontFamily.Name.ToLower(CultureInfo.InvariantCulture).StartsWith(familyName.ToLower(CultureInfo.InvariantCulture)))
+                if (fontFamily.Name.ToUpperInvariant().StartsWith(familyName.ToUpperInvariant()))
                 {
-                    if (_glyphTypefaceCache.TryGetValue(fontFamily.Name, out glyphTypefaces) &&
+                    familyName = fontFamily.Name.ToUpperInvariant();
+
+                    if (_glyphTypefaceCache.TryGetValue(familyName, out glyphTypefaces) &&
                         TryGetNearestMatch(glyphTypefaces, key, out glyphTypeface))
                     {
                         return true;
diff --git a/src/Avalonia.Base/Media/Fonts/SystemFontCollection.cs b/src/Avalonia.Base/Media/Fonts/SystemFontCollection.cs
index fd332c6ebe..1687deb37b 100644
--- a/src/Avalonia.Base/Media/Fonts/SystemFontCollection.cs
+++ b/src/Avalonia.Base/Media/Fonts/SystemFontCollection.cs
@@ -42,6 +42,8 @@ namespace Avalonia.Media.Fonts
                 familyName = _fontManager.DefaultFontFamilyName;
             }
 
+            familyName = familyName.ToUpperInvariant();
+
             var key = new FontCollectionKey(style, weight, stretch);
 
             if (_glyphTypefaceCache.TryGetValue(familyName, out var glyphTypefaces))