diff --git a/Userland/Libraries/LibWeb/CMakeLists.txt b/Userland/Libraries/LibWeb/CMakeLists.txt
index 7e219dc4a8..ea774a9bc7 100644
--- a/Userland/Libraries/LibWeb/CMakeLists.txt
+++ b/Userland/Libraries/LibWeb/CMakeLists.txt
@@ -11,6 +11,7 @@ set(SOURCES
     Bindings/Wrappable.cpp
     CSS/CSSImportRule.cpp
     CSS/CSSRule.cpp
+    CSS/CSSStyleDeclaration.cpp
     CSS/CSSStyleRule.cpp
     CSS/CSSStyleSheet.cpp
     CSS/DefaultStyleSheetSource.cpp
@@ -24,7 +25,6 @@ set(SOURCES
     CSS/QuirksModeStyleSheetSource.cpp
     CSS/Selector.cpp
     CSS/SelectorEngine.cpp
-    CSS/StyleDeclaration.cpp
     CSS/StyleInvalidator.cpp
     CSS/StyleProperties.cpp
     CSS/StyleResolver.cpp
diff --git a/Userland/Libraries/LibWeb/CSS/CSSRule.h b/Userland/Libraries/LibWeb/CSS/CSSRule.h
index de2a365252..63fa5c1868 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSRule.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSRule.h
@@ -28,8 +28,8 @@
 
 #include <AK/RefCounted.h>
 #include <AK/String.h>
+#include <LibWeb/CSS/CSSStyleDeclaration.h>
 #include <LibWeb/CSS/Selector.h>
-#include <LibWeb/CSS/StyleDeclaration.h>
 
 namespace Web::CSS {
 
diff --git a/Userland/Libraries/LibWeb/CSS/StyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
similarity index 89%
rename from Userland/Libraries/LibWeb/CSS/StyleDeclaration.cpp
rename to Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
index eb56b94625..04b291298a 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
@@ -24,16 +24,16 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <LibWeb/CSS/StyleDeclaration.h>
+#include <LibWeb/CSS/CSSStyleDeclaration.h>
 
 namespace Web::CSS {
 
-StyleDeclaration::StyleDeclaration(Vector<StyleProperty>&& properties)
+CSSStyleDeclaration::CSSStyleDeclaration(Vector<StyleProperty>&& properties)
     : m_properties(move(properties))
 {
 }
 
-StyleDeclaration::~StyleDeclaration()
+CSSStyleDeclaration::~CSSStyleDeclaration()
 {
 }
 
diff --git a/Userland/Libraries/LibWeb/CSS/StyleDeclaration.h b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
similarity index 85%
rename from Userland/Libraries/LibWeb/CSS/StyleDeclaration.h
rename to Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
index 787429eb15..b81b08dcdc 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleDeclaration.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
@@ -38,19 +38,19 @@ struct StyleProperty {
     bool important { false };
 };
 
-class StyleDeclaration : public RefCounted<StyleDeclaration> {
+class CSSStyleDeclaration : public RefCounted<CSSStyleDeclaration> {
 public:
-    static NonnullRefPtr<StyleDeclaration> create(Vector<StyleProperty>&& properties)
+    static NonnullRefPtr<CSSStyleDeclaration> create(Vector<StyleProperty>&& properties)
     {
-        return adopt(*new StyleDeclaration(move(properties)));
+        return adopt(*new CSSStyleDeclaration(move(properties)));
     }
 
-    ~StyleDeclaration();
+    ~CSSStyleDeclaration();
 
     const Vector<StyleProperty>& properties() const { return m_properties; }
 
 private:
-    explicit StyleDeclaration(Vector<StyleProperty>&&);
+    explicit CSSStyleDeclaration(Vector<StyleProperty>&&);
 
     Vector<StyleProperty> m_properties;
 };
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
index daaf83d467..72e3791deb 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
@@ -28,7 +28,7 @@
 
 namespace Web::CSS {
 
-CSSStyleRule::CSSStyleRule(Vector<Selector>&& selectors, NonnullRefPtr<StyleDeclaration>&& declaration)
+CSSStyleRule::CSSStyleRule(Vector<Selector>&& selectors, NonnullRefPtr<CSSStyleDeclaration>&& declaration)
     : m_selectors(move(selectors))
     , m_declaration(move(declaration))
 {
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
index bfee3c0b6d..e8db816f6c 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
@@ -29,8 +29,8 @@
 
 #include <AK/NonnullRefPtrVector.h>
 #include <LibWeb/CSS/CSSRule.h>
+#include <LibWeb/CSS/CSSStyleDeclaration.h>
 #include <LibWeb/CSS/Selector.h>
-#include <LibWeb/CSS/StyleDeclaration.h>
 
 namespace Web::CSS {
 
@@ -39,7 +39,7 @@ class CSSStyleRule : public CSSRule {
     AK_MAKE_NONMOVABLE(CSSStyleRule);
 
 public:
-    static NonnullRefPtr<CSSStyleRule> create(Vector<Selector>&& selectors, NonnullRefPtr<StyleDeclaration>&& declaration)
+    static NonnullRefPtr<CSSStyleRule> create(Vector<Selector>&& selectors, NonnullRefPtr<CSSStyleDeclaration>&& declaration)
     {
         return adopt(*new CSSStyleRule(move(selectors), move(declaration)));
     }
@@ -47,16 +47,16 @@ public:
     ~CSSStyleRule();
 
     const Vector<Selector>& selectors() const { return m_selectors; }
-    const StyleDeclaration& declaration() const { return m_declaration; }
+    const CSSStyleDeclaration& declaration() const { return m_declaration; }
 
     virtual StringView class_name() const { return "CSSStyleRule"; };
     virtual Type type() const { return Type::Style; };
 
 private:
-    CSSStyleRule(Vector<Selector>&&, NonnullRefPtr<StyleDeclaration>&&);
+    CSSStyleRule(Vector<Selector>&&, NonnullRefPtr<CSSStyleDeclaration>&&);
 
     Vector<Selector> m_selectors;
-    NonnullRefPtr<StyleDeclaration> m_declaration;
+    NonnullRefPtr<CSSStyleDeclaration> m_declaration;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
index f565186ef2..3c6b0e15f3 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
@@ -808,7 +808,7 @@ public:
             return;
         }
 
-        rules.append(CSS::CSSStyleRule::create(move(current_rule.selectors), CSS::StyleDeclaration::create(move(current_rule.properties))));
+        rules.append(CSS::CSSStyleRule::create(move(current_rule.selectors), CSS::CSSStyleDeclaration::create(move(current_rule.properties))));
     }
 
     Optional<String> parse_string()
@@ -947,7 +947,7 @@ public:
         return CSS::CSSStyleSheet::create(move(rules));
     }
 
-    RefPtr<CSS::StyleDeclaration> parse_standalone_declaration()
+    RefPtr<CSS::CSSStyleDeclaration> parse_standalone_declaration()
     {
         consume_whitespace_or_comments();
         for (;;) {
@@ -958,7 +958,7 @@ public:
             if (!peek())
                 break;
         }
-        return CSS::StyleDeclaration::create(move(current_rule.properties));
+        return CSS::CSSStyleDeclaration::create(move(current_rule.properties));
     }
 
 private:
@@ -993,10 +993,10 @@ RefPtr<CSS::CSSStyleSheet> parse_css(const CSS::ParsingContext& context, const S
     return parser.parse_sheet();
 }
 
-RefPtr<CSS::StyleDeclaration> parse_css_declaration(const CSS::ParsingContext& context, const StringView& css)
+RefPtr<CSS::CSSStyleDeclaration> parse_css_declaration(const CSS::ParsingContext& context, const StringView& css)
 {
     if (css.is_empty())
-        return CSS::StyleDeclaration::create({});
+        return CSS::CSSStyleDeclaration::create({});
     CSSParser parser(context, css);
     return parser.parse_standalone_declaration();
 }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.h b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.h
index bf1da4229e..e03c83ba59 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.h
+++ b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.h
@@ -49,7 +49,7 @@ private:
 namespace Web {
 
 RefPtr<CSS::CSSStyleSheet> parse_css(const CSS::ParsingContext&, const StringView&);
-RefPtr<CSS::StyleDeclaration> parse_css_declaration(const CSS::ParsingContext&, const StringView&);
+RefPtr<CSS::CSSStyleDeclaration> parse_css_declaration(const CSS::ParsingContext&, const StringView&);
 RefPtr<CSS::StyleValue> parse_css_value(const CSS::ParsingContext&, const StringView&, CSS::PropertyID property_id = CSS::PropertyID::Invalid);
 Optional<CSS::Selector> parse_selector(const CSS::ParsingContext&, const StringView&);
 
diff --git a/Userland/Libraries/LibWeb/DOM/Element.h b/Userland/Libraries/LibWeb/DOM/Element.h
index a9462caf5b..fdafd19fd8 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.h
+++ b/Userland/Libraries/LibWeb/DOM/Element.h
@@ -90,7 +90,7 @@ public:
     const CSS::StyleProperties* specified_css_values() const { return m_specified_css_values.ptr(); }
     NonnullRefPtr<CSS::StyleProperties> computed_style();
 
-    const CSS::StyleDeclaration* inline_style() const { return m_inline_style; }
+    const CSS::CSSStyleDeclaration* inline_style() const { return m_inline_style; }
 
     // FIXME: innerHTML also appears on shadow roots. https://w3c.github.io/DOM-Parsing/#dom-innerhtml
     String inner_html() const;
@@ -116,7 +116,7 @@ private:
     QualifiedName m_qualified_name;
     Vector<Attribute> m_attributes;
 
-    RefPtr<CSS::StyleDeclaration> m_inline_style;
+    RefPtr<CSS::CSSStyleDeclaration> m_inline_style;
 
     RefPtr<CSS::StyleProperties> m_specified_css_values;
 
diff --git a/Userland/Libraries/LibWeb/Forward.h b/Userland/Libraries/LibWeb/Forward.h
index 5a90a41bb0..3b8e4c4222 100644
--- a/Userland/Libraries/LibWeb/Forward.h
+++ b/Userland/Libraries/LibWeb/Forward.h
@@ -30,11 +30,11 @@
 namespace Web::CSS {
 class CSSRule;
 class CSSImportRule;
+class CSSStyleDeclaration;
 class CSSStyleRule;
 class CSSStyleSheet;
 class Length;
 class Selector;
-class StyleDeclaration;
 class StyleProperties;
 class StyleResolver;
 class StyleSheet;