diff --git a/Userland/Libraries/LibWebView/OutOfProcessWebView.cpp b/Userland/Libraries/LibWebView/OutOfProcessWebView.cpp
index 9714cbb9cb..4f5e6d0449 100644
--- a/Userland/Libraries/LibWebView/OutOfProcessWebView.cpp
+++ b/Userland/Libraries/LibWebView/OutOfProcessWebView.cpp
@@ -516,4 +516,9 @@ void OutOfProcessWebView::set_content_scales_to_viewport(bool b)
     m_content_scales_to_viewport = b;
 }
 
+void OutOfProcessWebView::set_user_style_sheet(String source)
+{
+    client().async_set_user_style(source);
+}
+
 }
diff --git a/Userland/Libraries/LibWebView/OutOfProcessWebView.h b/Userland/Libraries/LibWebView/OutOfProcessWebView.h
index 56ea39aa65..8b6377d148 100644
--- a/Userland/Libraries/LibWebView/OutOfProcessWebView.h
+++ b/Userland/Libraries/LibWebView/OutOfProcessWebView.h
@@ -54,6 +54,8 @@ public:
     // In practice, this means that OOPWV may render scaled stale versions of the content while resizing.
     void set_content_scales_to_viewport(bool);
 
+    void set_user_style_sheet(String source);
+
 private:
     OutOfProcessWebView();
 
diff --git a/Userland/Services/WebContent/ConnectionFromClient.cpp b/Userland/Services/WebContent/ConnectionFromClient.cpp
index 32ad6c3bec..9d106b031e 100644
--- a/Userland/Services/WebContent/ConnectionFromClient.cpp
+++ b/Userland/Services/WebContent/ConnectionFromClient.cpp
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
  * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
  * Copyright (c) 2022, Tobias Christiansen <tobyase@serenityos.org>
  * Copyright (c) 2022, Tim Flynn <trflynn89@serenityos.org>
@@ -859,6 +859,11 @@ void ConnectionFromClient::toggle_media_controls_state()
     m_page_host->toggle_media_controls_state().release_value_but_fixme_should_propagate_errors();
 }
 
+void ConnectionFromClient::set_user_style(String const& source)
+{
+    m_page_host->set_user_style(source);
+}
+
 void ConnectionFromClient::inspect_accessibility_tree()
 {
     if (auto* doc = page().top_level_browsing_context().active_document()) {
diff --git a/Userland/Services/WebContent/ConnectionFromClient.h b/Userland/Services/WebContent/ConnectionFromClient.h
index be46ec61ce..fc86b45f52 100644
--- a/Userland/Services/WebContent/ConnectionFromClient.h
+++ b/Userland/Services/WebContent/ConnectionFromClient.h
@@ -102,6 +102,8 @@ private:
     virtual void toggle_media_loop_state() override;
     virtual void toggle_media_controls_state() override;
 
+    virtual void set_user_style(String const&) override;
+
     virtual Messages::WebContentServer::TakeDocumentScreenshotResponse take_document_screenshot() override;
 
     virtual Messages::WebContentServer::GetLocalStorageEntriesResponse get_local_storage_entries() override;
diff --git a/Userland/Services/WebContent/PageHost.cpp b/Userland/Services/WebContent/PageHost.cpp
index 0af50f8861..caa23f1bca 100644
--- a/Userland/Services/WebContent/PageHost.cpp
+++ b/Userland/Services/WebContent/PageHost.cpp
@@ -366,6 +366,11 @@ Web::WebIDL::ExceptionOr<void> PageHost::toggle_media_controls_state()
     return page().toggle_media_controls_state();
 }
 
+void PageHost::set_user_style(String source)
+{
+    page().set_user_style(source);
+}
+
 void PageHost::page_did_request_accept_dialog()
 {
     m_client.async_did_request_accept_dialog();
diff --git a/Userland/Services/WebContent/PageHost.h b/Userland/Services/WebContent/PageHost.h
index e412599084..9f58004992 100644
--- a/Userland/Services/WebContent/PageHost.h
+++ b/Userland/Services/WebContent/PageHost.h
@@ -56,6 +56,8 @@ public:
 
     [[nodiscard]] Gfx::Color background_color() const;
 
+    void set_user_style(String source);
+
 private:
     // ^PageClient
     virtual bool is_connection_open() const override;
diff --git a/Userland/Services/WebContent/WebContentServer.ipc b/Userland/Services/WebContent/WebContentServer.ipc
index a54f72ee02..ff497f7068 100644
--- a/Userland/Services/WebContent/WebContentServer.ipc
+++ b/Userland/Services/WebContent/WebContentServer.ipc
@@ -83,4 +83,6 @@ endpoint WebContentServer
     toggle_media_mute_state() =|
     toggle_media_loop_state() =|
     toggle_media_controls_state() =|
+
+    set_user_style(String source) =|
 }