diff --git a/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.cpp b/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.cpp
index b694cf8cece..3980ebab55a 100644
--- a/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.cpp
+++ b/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.cpp
@@ -31,7 +31,22 @@ AudioBufferSourceNode::~AudioBufferSourceNode() = default;
 // https://webaudio.github.io/web-audio-api/#dom-audiobuffersourcenode-buffer
 WebIDL::ExceptionOr<void> AudioBufferSourceNode::set_buffer(GC::Ptr<AudioBuffer> buffer)
 {
-    m_buffer = buffer;
+    // 1. Let new buffer be the AudioBuffer or null value to be assigned to buffer.
+    auto new_buffer = buffer;
+
+    // 2. If new buffer is not null and [[buffer set]] is true, throw an InvalidStateError and abort these steps.
+    if (new_buffer && m_buffer_set)
+        return WebIDL::InvalidStateError::create(realm(), "Buffer has already been set"_string);
+
+    // 3. If new buffer is not null, set [[buffer set]] to true.
+    if (new_buffer)
+        m_buffer_set = true;
+
+    // 4. Assign new buffer to the buffer attribute.
+    m_buffer = new_buffer;
+
+    // FIXME: 5. If start() has previously been called on this node, perform the operation acquire the content on buffer.
+
     return {};
 }
 
diff --git a/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.h b/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.h
index 69517bf5d7b..e0fb0782fe5 100644
--- a/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.h
+++ b/Libraries/LibWeb/WebAudio/AudioBufferSourceNode.h
@@ -60,6 +60,8 @@ private:
     GC::Ref<AudioParam> m_playback_rate;
     GC::Ref<AudioParam> m_detune;
     bool m_loop { false };
+    // https://webaudio.github.io/web-audio-api/#dom-audiobuffersourcenode-buffer-set-slot
+    bool m_buffer_set { false };
     double m_loop_start { 0.0 };
     double m_loop_end { 0.0 };
 };
diff --git a/Tests/LibWeb/Text/expected/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.txt b/Tests/LibWeb/Text/expected/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.txt
new file mode 100644
index 00000000000..d21f0791922
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.txt
@@ -0,0 +1,27 @@
+Harness status: OK
+
+Found 22 tests
+
+22 Pass
+Pass	# AUDIT TASK RUNNER STARTED.
+Pass	Executing "validate .buffer"
+Pass	Audit report
+Pass	> [validate .buffer] Validatation of AudioBuffer in .buffer attribute setter
+Pass	  source.buffer = 57 threw TypeError: "Not an object of type AudioBuffer".
+Pass	  source.buffer = null did not throw an exception.
+Pass	  source.buffer = buffer did not throw an exception.
+Pass	  source.buffer = new buffer threw InvalidStateError: "Buffer has already been set".
+Pass	  source.buffer = null again did not throw an exception.
+Pass	  source.buffer = buffer again threw InvalidStateError: "Buffer has already been set".
+Pass	  source.buffer = null after setting to null did not throw an exception.
+Pass	  Setting source with mono buffer did not throw an exception.
+Pass	  Setting source with stereo buffer did not throw an exception.
+Pass	  Setting source with 3 channels buffer did not throw an exception.
+Pass	  Setting source with 4 channels buffer did not throw an exception.
+Pass	  Setting source with 5 channels buffer did not throw an exception.
+Pass	  Setting source with 6 channels buffer did not throw an exception.
+Pass	  Setting source with 7 channels buffer did not throw an exception.
+Pass	  Setting source with 8 channels buffer did not throw an exception.
+Pass	  Setting source with 9 channels buffer did not throw an exception.
+Pass	< [validate .buffer] All assertions passed. (total 16 assertions)
+Pass	# AUDIT TASK RUNNER FINISHED: 1 tasks ran successfully.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.html b/Tests/LibWeb/Text/input/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.html
new file mode 100644
index 00000000000..e37f932c6eb
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-channels.html
@@ -0,0 +1,97 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>
+      audiobuffersource-channels.html
+    </title>
+    <script src="../../../resources/testharness.js"></script>
+    <script src="../../../resources/testharnessreport.js"></script>
+    <script src="../../../webaudio/resources/audit-util.js"></script>
+    <script src="../../../webaudio/resources/audit.js"></script>
+  </head>
+  <body>
+    <script id="layout-test-code">
+      let audit = Audit.createTaskRunner();
+      let context;
+      let source;
+
+      audit.define(
+          {
+            label: 'validate .buffer',
+            description:
+                'Validatation of AudioBuffer in .buffer attribute setter'
+          },
+          function(task, should) {
+            context = new AudioContext();
+            source = context.createBufferSource();
+
+            // Make sure we can't set to something which isn't an AudioBuffer.
+            should(function() {
+              source.buffer = 57;
+            }, 'source.buffer = 57').throw(TypeError);
+
+            // It's ok to set the buffer to null.
+            should(function() {
+              source.buffer = null;
+            }, 'source.buffer = null').notThrow();
+
+            // Set the buffer to a valid AudioBuffer
+            let buffer =
+                new AudioBuffer({length: 128, sampleRate: context.sampleRate});
+
+            should(function() {
+              source.buffer = buffer;
+            }, 'source.buffer = buffer').notThrow();
+
+            // The buffer has been set; we can't set it again.
+            should(function() {
+              source.buffer =
+                  new AudioBuffer({length: 128, sampleRate: context.sampleRate})
+            }, 'source.buffer = new buffer').throw(DOMException, 'InvalidStateError');
+
+            // The buffer has been set; it's ok to set it to null.
+            should(function() {
+              source.buffer = null;
+            }, 'source.buffer = null again').notThrow();
+
+            // The buffer was already set (and set to null).  Can't set it
+            // again.
+            should(function() {
+              source.buffer = buffer;
+            }, 'source.buffer = buffer again').throw(DOMException, 'InvalidStateError');
+
+            // But setting to null is ok.
+            should(function() {
+            }, 'source.buffer = null after setting to null').notThrow();
+
+            // Check that mono buffer can be set.
+            should(function() {
+              let monoBuffer =
+                  context.createBuffer(1, 1024, context.sampleRate);
+              let testSource = context.createBufferSource();
+              testSource.buffer = monoBuffer;
+            }, 'Setting source with mono buffer').notThrow();
+
+            // Check that stereo buffer can be set.
+            should(function() {
+              let stereoBuffer =
+                  context.createBuffer(2, 1024, context.sampleRate);
+              let testSource = context.createBufferSource();
+              testSource.buffer = stereoBuffer;
+            }, 'Setting source with stereo buffer').notThrow();
+
+            // Check buffers with more than two channels.
+            for (let i = 3; i < 10; ++i) {
+              should(function() {
+                let buffer = context.createBuffer(i, 1024, context.sampleRate);
+                let testSource = context.createBufferSource();
+                testSource.buffer = buffer;
+              }, 'Setting source with ' + i + ' channels buffer').notThrow();
+            }
+            task.done();
+          });
+
+      audit.run();
+    </script>
+  </body>
+</html>