diff --git a/Libraries/LibWeb/HTML/AttributeNames.h b/Libraries/LibWeb/HTML/AttributeNames.h
index 6dc4c95cbca..c73d4e8bd1d 100644
--- a/Libraries/LibWeb/HTML/AttributeNames.h
+++ b/Libraries/LibWeb/HTML/AttributeNames.h
@@ -233,6 +233,7 @@ namespace AttributeNames {
     __ENUMERATE_HTML_ATTRIBUTE(rows)                       \
     __ENUMERATE_HTML_ATTRIBUTE(rowspan)                    \
     __ENUMERATE_HTML_ATTRIBUTE(rules)                      \
+    __ENUMERATE_HTML_ATTRIBUTE(sandbox)                    \
     __ENUMERATE_HTML_ATTRIBUTE(scheme)                     \
     __ENUMERATE_HTML_ATTRIBUTE(scope)                      \
     __ENUMERATE_HTML_ATTRIBUTE(scrollamount)               \
diff --git a/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp b/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
index 8249a8576c8..d352d2d92db 100644
--- a/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
@@ -8,6 +8,7 @@
 #include <LibURL/Origin.h>
 #include <LibWeb/Bindings/HTMLIFrameElementPrototype.h>
 #include <LibWeb/CSS/StyleValues/DisplayStyleValue.h>
+#include <LibWeb/DOM/DOMTokenList.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/Event.h>
 #include <LibWeb/HTML/BrowsingContext.h>
@@ -211,10 +212,20 @@ i32 HTMLIFrameElement::default_tab_index_value() const
     return 0;
 }
 
+// https://html.spec.whatwg.org/multipage/iframe-embed-object.html#dom-iframe-sandbox
+GC::Ref<DOM::DOMTokenList> HTMLIFrameElement::sandbox()
+{
+    // The sandbox IDL attribute must reflect the sandbox content attribute.
+    if (!m_sandbox)
+        m_sandbox = DOM::DOMTokenList::create(*this, HTML::AttributeNames::sandbox);
+    return *m_sandbox;
+}
+
 void HTMLIFrameElement::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visit_lazy_loading_element(visitor);
+    visitor.visit(m_sandbox);
 }
 
 void HTMLIFrameElement::set_current_navigation_was_lazy_loaded(bool value)
diff --git a/Libraries/LibWeb/HTML/HTMLIFrameElement.h b/Libraries/LibWeb/HTML/HTMLIFrameElement.h
index 2fd2c8158e4..085df19052c 100644
--- a/Libraries/LibWeb/HTML/HTMLIFrameElement.h
+++ b/Libraries/LibWeb/HTML/HTMLIFrameElement.h
@@ -31,6 +31,8 @@ public:
     Optional<HighResolutionTime::DOMHighResTimeStamp> const& pending_resource_start_time() const { return m_pending_resource_start_time; }
     void set_pending_resource_start_time(Optional<HighResolutionTime::DOMHighResTimeStamp> time) { m_pending_resource_start_time = time; }
 
+    GC::Ref<DOM::DOMTokenList> sandbox();
+
     virtual void visit_edges(Cell::Visitor&) override;
 
 private:
@@ -55,6 +57,8 @@ private:
 
     // https://html.spec.whatwg.org/multipage/iframe-embed-object.html#iframe-pending-resource-timing-start-time
     Optional<HighResolutionTime::DOMHighResTimeStamp> m_pending_resource_start_time = {};
+
+    GC::Ptr<DOM::DOMTokenList> m_sandbox;
 };
 
 void run_iframe_load_event_steps(HTML::HTMLIFrameElement&);
diff --git a/Libraries/LibWeb/HTML/HTMLIFrameElement.idl b/Libraries/LibWeb/HTML/HTMLIFrameElement.idl
index 205c4e7099e..9f00d92df8c 100644
--- a/Libraries/LibWeb/HTML/HTMLIFrameElement.idl
+++ b/Libraries/LibWeb/HTML/HTMLIFrameElement.idl
@@ -11,7 +11,7 @@ interface HTMLIFrameElement : HTMLElement {
     [CEReactions, Reflect, URL] attribute USVString src;
     [CEReactions, Reflect] attribute DOMString srcdoc;
     [CEReactions, Reflect] attribute DOMString name;
-    [FIXME, SameObject, PutForwards=value] readonly attribute DOMTokenList sandbox;
+    [SameObject, PutForwards=value] readonly attribute DOMTokenList sandbox;
     [CEReactions, Reflect] attribute DOMString allow;
     [CEReactions, Reflect=allowfullscreen] attribute boolean allowFullscreen;
     [CEReactions, Reflect] attribute DOMString width;
diff --git a/Tests/LibWeb/Text/expected/wpt-import/dom/lists/DOMTokenList-coverage-for-attributes.txt b/Tests/LibWeb/Text/expected/wpt-import/dom/lists/DOMTokenList-coverage-for-attributes.txt
index 9502f336e27..91f20a5ec51 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/dom/lists/DOMTokenList-coverage-for-attributes.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/dom/lists/DOMTokenList-coverage-for-attributes.txt
@@ -6,8 +6,7 @@ Rerun
 
 Found 175 tests
 
-174 Pass
-1 Fail
+175 Pass
 Details
 Result	Test Name	MessagePass	a.classList in http://www.w3.org/1999/xhtml namespace should be DOMTokenList.	
 Pass	area.classList in http://www.w3.org/1999/xhtml namespace should be DOMTokenList.	
@@ -117,7 +116,7 @@ Pass	th.htmlFor in null namespace should be undefined.
 Pass	a.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.	
 Pass	area.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.	
 Pass	link.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.	
-Fail	iframe.sandbox in http://www.w3.org/1999/xhtml namespace should be DOMTokenList.	
+Pass	iframe.sandbox in http://www.w3.org/1999/xhtml namespace should be DOMTokenList.	
 Pass	output.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.	
 Pass	td.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.	
 Pass	th.sandbox in http://www.w3.org/1999/xhtml namespace should be undefined.