diff --git a/Userland/Libraries/LibWeb/CSS/MediaList.cpp b/Userland/Libraries/LibWeb/CSS/MediaList.cpp
index 2999141b74..ca0a470c6a 100644
--- a/Userland/Libraries/LibWeb/CSS/MediaList.cpp
+++ b/Userland/Libraries/LibWeb/CSS/MediaList.cpp
@@ -34,7 +34,7 @@ JS::ThrowCompletionOr<void> MediaList::initialize(JS::Realm& realm)
 // https://www.w3.org/TR/cssom-1/#dom-medialist-mediatext
 DeprecatedString MediaList::media_text() const
 {
-    return serialize_a_media_query_list(m_media);
+    return serialize_a_media_query_list(m_media).release_value_but_fixme_should_propagate_errors().to_deprecated_string();
 }
 
 // https://www.w3.org/TR/cssom-1/#dom-medialist-mediatext
diff --git a/Userland/Libraries/LibWeb/CSS/MediaQuery.cpp b/Userland/Libraries/LibWeb/CSS/MediaQuery.cpp
index 20a1f0ac36..b7e328122c 100644
--- a/Userland/Libraries/LibWeb/CSS/MediaQuery.cpp
+++ b/Userland/Libraries/LibWeb/CSS/MediaQuery.cpp
@@ -379,17 +379,15 @@ bool MediaQuery::evaluate(HTML::Window const& window)
 }
 
 // https://www.w3.org/TR/cssom-1/#serialize-a-media-query-list
-DeprecatedString serialize_a_media_query_list(NonnullRefPtrVector<MediaQuery> const& media_queries)
+ErrorOr<String> serialize_a_media_query_list(NonnullRefPtrVector<MediaQuery> const& media_queries)
 {
     // 1. If the media query list is empty, then return the empty string.
     if (media_queries.is_empty())
-        return "";
+        return String {};
 
     // 2. Serialize each media query in the list of media queries, in the same order as they
     // appear in the media query list, and then serialize the list.
-    StringBuilder builder;
-    builder.join(", "sv, media_queries);
-    return builder.to_deprecated_string();
+    return String::join(", "sv, media_queries);
 }
 
 bool is_media_feature_name(StringView name)
diff --git a/Userland/Libraries/LibWeb/CSS/MediaQuery.h b/Userland/Libraries/LibWeb/CSS/MediaQuery.h
index ed31e57aa5..050c95cb8b 100644
--- a/Userland/Libraries/LibWeb/CSS/MediaQuery.h
+++ b/Userland/Libraries/LibWeb/CSS/MediaQuery.h
@@ -1,12 +1,11 @@
 /*
- * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
-#include <AK/DeprecatedFlyString.h>
 #include <AK/NonnullOwnPtrVector.h>
 #include <AK/NonnullRefPtr.h>
 #include <AK/Optional.h>
@@ -255,7 +254,7 @@ private:
     bool m_matches { false };
 };
 
-DeprecatedString serialize_a_media_query_list(NonnullRefPtrVector<MediaQuery> const&);
+ErrorOr<String> serialize_a_media_query_list(NonnullRefPtrVector<MediaQuery> const&);
 
 bool is_media_feature_name(StringView name);
 
diff --git a/Userland/Libraries/LibWeb/CSS/MediaQueryList.cpp b/Userland/Libraries/LibWeb/CSS/MediaQueryList.cpp
index c21f4c0bc2..127c50425c 100644
--- a/Userland/Libraries/LibWeb/CSS/MediaQueryList.cpp
+++ b/Userland/Libraries/LibWeb/CSS/MediaQueryList.cpp
@@ -45,7 +45,7 @@ void MediaQueryList::visit_edges(Cell::Visitor& visitor)
 // https://drafts.csswg.org/cssom-view/#dom-mediaquerylist-media
 DeprecatedString MediaQueryList::media() const
 {
-    return serialize_a_media_query_list(m_media);
+    return serialize_a_media_query_list(m_media).release_value_but_fixme_should_propagate_errors().to_deprecated_string();
 }
 
 // https://drafts.csswg.org/cssom-view/#dom-mediaquerylist-matches