diff --git a/Meta/gn/secondary/Userland/Libraries/LibGfx/BUILD.gn b/Meta/gn/secondary/Userland/Libraries/LibGfx/BUILD.gn
index f027701b560..b20fcb50216 100644
--- a/Meta/gn/secondary/Userland/Libraries/LibGfx/BUILD.gn
+++ b/Meta/gn/secondary/Userland/Libraries/LibGfx/BUILD.gn
@@ -72,6 +72,7 @@ shared_library("LibGfx") {
     "ImageFormats/ICOLoader.cpp",
     "ImageFormats/ILBMLoader.cpp",
     "ImageFormats/ISOBMFF/Boxes.cpp",
+    "ImageFormats/ISOBMFF/JPEG2000Boxes.cpp",
     "ImageFormats/ISOBMFF/Reader.cpp",
     "ImageFormats/ImageDecoder.cpp",
     "ImageFormats/JBIG2Loader.cpp",
diff --git a/Userland/Libraries/LibGfx/CMakeLists.txt b/Userland/Libraries/LibGfx/CMakeLists.txt
index 1fb695f601a..70228efbc6b 100644
--- a/Userland/Libraries/LibGfx/CMakeLists.txt
+++ b/Userland/Libraries/LibGfx/CMakeLists.txt
@@ -46,6 +46,7 @@ set(SOURCES
     ImageFormats/ILBMLoader.cpp
     ImageFormats/ImageDecoder.cpp
     ImageFormats/ISOBMFF/Boxes.cpp
+    ImageFormats/ISOBMFF/JPEG2000Boxes.cpp
     ImageFormats/ISOBMFF/Reader.cpp
     ImageFormats/JBIG2Loader.cpp
     ImageFormats/JPEGLoader.cpp
diff --git a/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.cpp b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.cpp
new file mode 100644
index 00000000000..13764a4c35e
--- /dev/null
+++ b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.cpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2024, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "JPEG2000Boxes.h"
+
+namespace Gfx::ISOBMFF {
+
+ErrorOr<void> JPEG2000SignatureBox::read_from_stream(BoxStream& stream)
+{
+    signature = TRY(stream.read_value<BigEndian<u32>>());
+    return {};
+}
+
+void JPEG2000SignatureBox::dump(String const& prepend) const
+{
+    Box::dump(prepend);
+    outln("{}- signature = {:#08x}", prepend, signature);
+}
+
+}
diff --git a/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.h b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.h
new file mode 100644
index 00000000000..511da0823da
--- /dev/null
+++ b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/JPEG2000Boxes.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2024, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include "Boxes.h"
+
+namespace Gfx::ISOBMFF {
+
+struct JPEG2000SignatureBox final : public Box {
+    BOX_SUBTYPE(JPEG2000SignatureBox);
+
+    u32 signature { 0 };
+};
+
+}
diff --git a/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/Reader.cpp b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/Reader.cpp
index 36ce4b5f1bb..6a66c7de3ed 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/Reader.cpp
+++ b/Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/Reader.cpp
@@ -5,6 +5,8 @@
  */
 
 #include "Reader.h"
+#include "JPEG2000Boxes.h"
+#include <AK/Function.h>
 
 namespace Gfx::ISOBMFF {
 
@@ -34,6 +36,9 @@ ErrorOr<BoxList> Reader::read_entire_file()
         case BoxType::JPEG2000HeaderBox:
             TRY(top_level_boxes.try_append(TRY(SuperBox::create_from_stream(box_header.type, box_stream))));
             break;
+        case BoxType::JPEG2000SignatureBox:
+            TRY(top_level_boxes.try_append(TRY(JPEG2000SignatureBox::create_from_stream(box_stream))));
+            break;
         default:
             TRY(top_level_boxes.try_append(TRY(UnknownBox::create_from_stream(box_header.type, box_stream))));
             break;