diff --git a/Libraries/LibWeb/CSS/CSSFontFaceRule.cpp b/Libraries/LibWeb/CSS/CSSFontFaceRule.cpp
index eb7d3046562..8123b7be199 100644
--- a/Libraries/LibWeb/CSS/CSSFontFaceRule.cpp
+++ b/Libraries/LibWeb/CSS/CSSFontFaceRule.cpp
@@ -34,6 +34,15 @@ void CSSFontFaceRule::initialize(JS::Realm& realm)
     WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSFontFaceRule);
 }
 
+bool CSSFontFaceRule::is_valid() const
+{
+    // @font-face rules require a font-family and src descriptor; if either of these are missing, the @font-face rule
+    // must not be considered when performing the font matching algorithm.
+    // https://drafts.csswg.org/css-fonts-4/#font-face-rule
+    return !m_style->descriptor(DescriptorID::FontFamily).is_null()
+        && !m_style->descriptor(DescriptorID::Src).is_null();
+}
+
 ParsedFontFace CSSFontFaceRule::font_face() const
 {
     return ParsedFontFace::from_descriptors(m_style);
diff --git a/Libraries/LibWeb/CSS/CSSFontFaceRule.h b/Libraries/LibWeb/CSS/CSSFontFaceRule.h
index fc6894360a8..69c9308f6df 100644
--- a/Libraries/LibWeb/CSS/CSSFontFaceRule.h
+++ b/Libraries/LibWeb/CSS/CSSFontFaceRule.h
@@ -22,6 +22,7 @@ public:
 
     virtual ~CSSFontFaceRule() override = default;
 
+    bool is_valid() const;
     ParsedFontFace font_face() const;
     CSSStyleDeclaration* style() { return m_style; }
 
diff --git a/Libraries/LibWeb/CSS/StyleComputer.cpp b/Libraries/LibWeb/CSS/StyleComputer.cpp
index c8a8426f975..e58c0dfa56f 100644
--- a/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -3061,8 +3061,10 @@ void StyleComputer::load_fonts_from_sheet(CSSStyleSheet& sheet)
     for (auto const& rule : sheet.rules()) {
         if (!is<CSSFontFaceRule>(*rule))
             continue;
-        auto font_loader = load_font_face(static_cast<CSSFontFaceRule const&>(*rule).font_face());
-        if (font_loader.has_value()) {
+        auto const& font_face_rule = static_cast<CSSFontFaceRule const&>(*rule);
+        if (!font_face_rule.is_valid())
+            continue;
+        if (auto font_loader = load_font_face(font_face_rule.font_face()); font_loader.has_value()) {
             sheet.add_associated_font_loader(font_loader.value());
         }
     }
diff --git a/Libraries/LibWeb/Dump.cpp b/Libraries/LibWeb/Dump.cpp
index 4625bb8c3f3..2803277488f 100644
--- a/Libraries/LibWeb/Dump.cpp
+++ b/Libraries/LibWeb/Dump.cpp
@@ -702,6 +702,9 @@ void dump_rule(StringBuilder& builder, CSS::CSSRule const& rule, int indent_leve
 void dump_font_face_rule(StringBuilder& builder, CSS::CSSFontFaceRule const& rule, int indent_levels)
 {
     auto const font_face = rule.font_face();
+    indent(builder, indent_levels + 1);
+    builder.appendff("VALID: {}\n", rule.is_valid());
+
     indent(builder, indent_levels + 1);
     builder.appendff("font-family: {}\n", font_face.font_family());