diff --git a/Meta/gn/secondary/Userland/Libraries/LibWeb/Streams/BUILD.gn b/Meta/gn/secondary/Userland/Libraries/LibWeb/Streams/BUILD.gn
index acdfd65f3a..7369143eb6 100644
--- a/Meta/gn/secondary/Userland/Libraries/LibWeb/Streams/BUILD.gn
+++ b/Meta/gn/secondary/Userland/Libraries/LibWeb/Streams/BUILD.gn
@@ -3,6 +3,8 @@ source_set("Streams") {
   deps = [ "//Userland/Libraries/LibWeb:all_generated" ]
   sources = [
     "AbstractOperations.cpp",
+    "ByteLengthQueuingStrategy.cpp",
+    "CountQueuingStrategy.cpp",
     "ReadableByteStreamController.cpp",
     "ReadableStream.cpp",
     "ReadableStreamBYOBReader.cpp",
@@ -10,6 +12,9 @@ source_set("Streams") {
     "ReadableStreamDefaultController.cpp",
     "ReadableStreamDefaultReader.cpp",
     "ReadableStreamGenericReader.cpp",
+    "TransformStream.cpp",
+    "TransformStreamDefaultController.cpp",
+    "Transformer.cpp",
     "UnderlyingSink.cpp",
     "UnderlyingSource.cpp",
     "WritableStream.cpp",
diff --git a/Meta/gn/secondary/Userland/Libraries/LibWeb/idl_files.gni b/Meta/gn/secondary/Userland/Libraries/LibWeb/idl_files.gni
index 4a5f1f5ffd..ac139ac698 100644
--- a/Meta/gn/secondary/Userland/Libraries/LibWeb/idl_files.gni
+++ b/Meta/gn/secondary/Userland/Libraries/LibWeb/idl_files.gni
@@ -209,12 +209,16 @@ standard_idl_files = get_path_info(
           "//Userland/Libraries/LibWeb/PerformanceTimeline/PerformanceEntry.idl",
           "//Userland/Libraries/LibWeb/RequestIdleCallback/IdleDeadline.idl",
           "//Userland/Libraries/LibWeb/ResizeObserver/ResizeObserver.idl",
+          "//Userland/Libraries/LibWeb/Streams/ByteLengthQueuingStrategy.idl",
+          "//Userland/Libraries/LibWeb/Streams/CountQueuingStrategy.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableStream.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBRequest.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultController.idl",
           "//Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultReader.idl",
+          "//Userland/Libraries/LibWeb/Streams/TransformStream.idl",
+          "//Userland/Libraries/LibWeb/Streams/TransformStreamDefaultController.idl",
           "//Userland/Libraries/LibWeb/Streams/WritableStream.idl",
           "//Userland/Libraries/LibWeb/Streams/WritableStreamDefaultWriter.idl",
           "//Userland/Libraries/LibWeb/SVG/SVGAnimatedLength.idl",