diff --git a/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp b/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
index 1fe76a2751d..82dbd566eae 100644
--- a/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
+++ b/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
@@ -119,7 +119,7 @@ WebIDL::ExceptionOr<void> PropertyOwningCSSStyleDeclaration::set_property(String
 
     // 3. If value is the empty string, invoke removeProperty() with property as argument and return.
     if (value.is_empty()) {
-        MUST(remove_property(property_id));
+        MUST(remove_property(property_name));
         return {};
     }
 
@@ -177,8 +177,12 @@ WebIDL::ExceptionOr<void> PropertyOwningCSSStyleDeclaration::set_property(String
 }
 
 // https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-removeproperty
-WebIDL::ExceptionOr<String> PropertyOwningCSSStyleDeclaration::remove_property(PropertyID property_id)
+WebIDL::ExceptionOr<String> PropertyOwningCSSStyleDeclaration::remove_property(StringView property_name)
 {
+    auto property_id = property_id_from_string(property_name);
+    if (!property_id.has_value())
+        return String {};
+
     // 1. If the computed flag is set, then throw a NoModificationAllowedError exception.
     // NOTE: This is handled by the virtual override in ResolvedCSSStyleDeclaration.
 
@@ -186,8 +190,7 @@ WebIDL::ExceptionOr<String> PropertyOwningCSSStyleDeclaration::remove_property(P
     // NOTE: We've already converted it to a PropertyID enum value.
 
     // 3. Let value be the return value of invoking getPropertyValue() with property as argument.
-    // FIXME: The trip through string_from_property_id() here is silly.
-    auto value = get_property_value(string_from_property_id(property_id));
+    auto value = get_property_value(property_name);
 
     // 4. Let removed be false.
     bool removed = false;
@@ -197,7 +200,12 @@ WebIDL::ExceptionOr<String> PropertyOwningCSSStyleDeclaration::remove_property(P
     //           2. Remove that CSS declaration and let removed be true.
 
     // 6. Otherwise, if property is a case-sensitive match for a property name of a CSS declaration in the declarations, remove that CSS declaration and let removed be true.
-    removed = m_properties.remove_first_matching([&](auto& entry) { return entry.property_id == property_id; });
+    if (property_id == PropertyID::Custom) {
+        auto custom_name = FlyString::from_utf8_without_validation(property_name.bytes());
+        removed = m_custom_properties.remove(custom_name);
+    } else {
+        removed = m_properties.remove_first_matching([&](auto& entry) { return entry.property_id == property_id; });
+    }
 
     // 7. If removed is true, Update style attribute for the CSS declaration block.
     if (removed)
@@ -321,12 +329,9 @@ WebIDL::ExceptionOr<void> CSSStyleDeclaration::set_property(PropertyID property_
     return set_property(string_from_property_id(property_id), css_text, priority);
 }
 
-WebIDL::ExceptionOr<String> CSSStyleDeclaration::remove_property(StringView property_name)
+WebIDL::ExceptionOr<String> CSSStyleDeclaration::remove_property(PropertyID property_name)
 {
-    auto property_id = property_id_from_string(property_name);
-    if (!property_id.has_value())
-        return String {};
-    return remove_property(property_id.value());
+    return remove_property(string_from_property_id(property_name));
 }
 
 // https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-csstext
diff --git a/Libraries/LibWeb/CSS/CSSStyleDeclaration.h b/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
index f94660dcdf5..32a898d50dc 100644
--- a/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
+++ b/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
@@ -32,10 +32,10 @@ public:
     virtual Optional<StyleProperty> custom_property(FlyString const& custom_property_name) const = 0;
 
     virtual WebIDL::ExceptionOr<void> set_property(PropertyID, StringView css_text, StringView priority = ""sv);
-    virtual WebIDL::ExceptionOr<String> remove_property(PropertyID) = 0;
+    virtual WebIDL::ExceptionOr<String> remove_property(PropertyID);
 
     virtual WebIDL::ExceptionOr<void> set_property(StringView property_name, StringView css_text, StringView priority) = 0;
-    virtual WebIDL::ExceptionOr<String> remove_property(StringView property_name);
+    virtual WebIDL::ExceptionOr<String> remove_property(StringView property_name) = 0;
 
     String get_property_value(StringView property) const;
     StringView get_property_priority(StringView property) const;
@@ -79,8 +79,7 @@ public:
     virtual Optional<StyleProperty> custom_property(FlyString const& custom_property_name) const override { return m_custom_properties.get(custom_property_name); }
 
     virtual WebIDL::ExceptionOr<void> set_property(StringView property_name, StringView css_text, StringView priority) override;
-    virtual WebIDL::ExceptionOr<String> remove_property(PropertyID) override;
-
+    virtual WebIDL::ExceptionOr<String> remove_property(StringView property_name) override;
     Vector<StyleProperty> const& properties() const { return m_properties; }
     HashMap<FlyString, StyleProperty> const& custom_properties() const { return m_custom_properties; }
 
diff --git a/Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-custom-properties.txt b/Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-custom-properties.txt
index c8d606fffe0..dde24163aa6 100644
--- a/Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-custom-properties.txt
+++ b/Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-custom-properties.txt
@@ -1,2 +1,3 @@
 style.getPropertyValue(--redcolor)=red
 rgb(255, 0, 0)
+rgba(0, 0, 0, 0)
diff --git a/Tests/LibWeb/Text/input/css/CSSStyleDeclaration-custom-properties.html b/Tests/LibWeb/Text/input/css/CSSStyleDeclaration-custom-properties.html
index 2c4942ddbd6..929250da074 100644
--- a/Tests/LibWeb/Text/input/css/CSSStyleDeclaration-custom-properties.html
+++ b/Tests/LibWeb/Text/input/css/CSSStyleDeclaration-custom-properties.html
@@ -16,5 +16,8 @@
         document.body.appendChild(div);
 
         println(getComputedStyle(nested).backgroundColor);
+
+        div.style.removeProperty("--redcolor");
+        println(getComputedStyle(nested).backgroundColor);
     });
 </script>
\ No newline at end of file