diff --git a/Tests/LibWeb/Text/expected/css/CSSStyleSheet-removeRule.txt b/Tests/LibWeb/Text/expected/css/CSSStyleSheet-removeRule.txt
new file mode 100644
index 0000000000..2a83cb2bf5
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/css/CSSStyleSheet-removeRule.txt
@@ -0,0 +1,12 @@
+Exception thrown when removeRule() called on empty sheet: IndexSizeError
+Rule count after adding 3 rules: 3
+Rule text: .test { padding: 10px; }
+Rule text: .test { margin: 5px; }
+Rule text: .test { font-size: 14px; }
+Rule count after calling removeRule with no arguments: 2
+Rule text: .test { margin: 5px; }
+Rule text: .test { font-size: 14px; }
+Rule count after calling removeRule with explicit index: 1
+Rule text: .test { margin: 5px; }
+Exception thrown when given a negative index: IndexSizeError
+Exception thrown when index out of range: IndexSizeError
diff --git a/Tests/LibWeb/Text/input/css/CSSStyleSheet-removeRule.html b/Tests/LibWeb/Text/input/css/CSSStyleSheet-removeRule.html
new file mode 100644
index 0000000000..83dbea49a4
--- /dev/null
+++ b/Tests/LibWeb/Text/input/css/CSSStyleSheet-removeRule.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        const sheet = new CSSStyleSheet();
+        try {
+            sheet.removeRule();
+            println("FAIL");
+        } catch (e) {
+            println(`Exception thrown when removeRule() called on empty sheet: ${e.name}`);
+        }
+
+        sheet.addRule(".test", "padding: 10px");
+        sheet.addRule(".test", "margin: 5px");
+        sheet.addRule(".test", "font-size: 14px");
+        println(`Rule count after adding 3 rules: ${sheet.cssRules.length}`);
+        for (const rule of sheet.cssRules) {
+            println(`Rule text: ${rule.cssText}`);
+        }
+        sheet.removeRule();
+        println(`Rule count after calling removeRule with no arguments: ${sheet.cssRules.length}`);
+        for (const rule of sheet.cssRules) {
+            println(`Rule text: ${rule.cssText}`);
+        }
+        sheet.removeRule(1);
+        println(`Rule count after calling removeRule with explicit index: ${sheet.cssRules.length}`);
+        println(`Rule text: ${sheet.cssRules[0].cssText}`);
+        try {
+            sheet.removeRule(-1);
+            println("FAIL");
+        } catch (e) {
+            println(`Exception thrown when given a negative index: ${e.name}`);
+        }
+        try {
+            sheet.removeRule(1);
+            println("FAIL");
+        } catch (e) {
+            println(`Exception thrown when index out of range: ${e.name}`);
+        }
+    });
+</script>
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.cpp b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
index 2f4a5eaff7..0a49ab9bbc 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
@@ -286,10 +286,10 @@ WebIDL::ExceptionOr<WebIDL::Long> CSSStyleSheet::add_rule(Optional<String> selec
 }
 
 // https://www.w3.org/TR/cssom/#dom-cssstylesheet-removerule
-WebIDL::ExceptionOr<void> CSSStyleSheet::remove_rule(unsigned index)
+WebIDL::ExceptionOr<void> CSSStyleSheet::remove_rule(Optional<WebIDL::UnsignedLong> index)
 {
     // The removeRule(index) method must run the same steps as deleteRule().
-    return delete_rule(index);
+    return delete_rule(index.value_or(0));
 }
 
 void CSSStyleSheet::for_each_effective_style_rule(Function<void(CSSStyleRule const&)> const& callback) const
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.h b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.h
index 0621f9a535..9f02ff8da5 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.h
@@ -51,7 +51,7 @@ public:
 
     WebIDL::ExceptionOr<unsigned> insert_rule(StringView rule, unsigned index);
     WebIDL::ExceptionOr<WebIDL::Long> add_rule(Optional<String> selector, Optional<String> style, Optional<WebIDL::UnsignedLong> index);
-    WebIDL::ExceptionOr<void> remove_rule(unsigned index);
+    WebIDL::ExceptionOr<void> remove_rule(Optional<WebIDL::UnsignedLong> index);
     WebIDL::ExceptionOr<void> delete_rule(unsigned index);
 
     JS::NonnullGCPtr<JS::Promise> replace(String text);
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.idl b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.idl
index 8dcce0584f..c7f223b7b9 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.idl
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleSheet.idl
@@ -19,7 +19,7 @@ interface CSSStyleSheet : StyleSheet {
     // https://drafts.csswg.org/cssom/#legacy-css-style-sheet-members
     [SameObject, ImplementedAs=css_rules] readonly attribute CSSRuleList rules;
     long addRule(optional DOMString selector = "undefined", optional DOMString style = "undefined", optional unsigned long index);
-    undefined removeRule(unsigned long index);
+    undefined removeRule(optional unsigned long index);
 };
 
 dictionary CSSStyleSheetInit {
