diff --git a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.cpp b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.cpp
index 7c9e5d6cf4..e4a543d7c1 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.cpp
+++ b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.cpp
@@ -30,6 +30,17 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<ReadableStreamBYOBReader>> ReadableStreamBY
     return reader;
 }
 
+// https://streams.spec.whatwg.org/#byob-reader-release-lock
+void ReadableStreamBYOBReader::release_lock()
+{
+    // 1. If this.[[stream]] is undefined, return.
+    if (!m_stream)
+        return;
+
+    // 2. Perform ! ReadableStreamBYOBReaderRelease(this).
+    readable_stream_byob_reader_release(*this);
+}
+
 void ReadableStreamBYOBReader::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
diff --git a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.h b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.h
index ad6597de34..7187f8e6c6 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.h
+++ b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.h
@@ -41,6 +41,8 @@ public:
 
     virtual ~ReadableStreamBYOBReader() override = default;
 
+    void release_lock();
+
     Vector<NonnullRefPtr<ReadIntoRequest>>& read_into_requests() { return m_read_into_requests; }
 
 private:
diff --git a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl
index 96a6d4e121..f2039ee1a4 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl
+++ b/Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl
@@ -8,6 +8,6 @@ interface ReadableStreamBYOBReader {
 
     // FIXME: Implement
     // Promise<ReadableStreamReadResult> read(ArrayBufferView view);
-    // undefined releaseLock();
+    undefined releaseLock();
 };
 ReadableStreamBYOBReader includes ReadableStreamGenericReader;