diff --git a/ext/lib.rs b/ext/lib.rs
index 5a70d1c..b7231c5 100644
--- a/ext/lib.rs
+++ b/ext/lib.rs
@@ -45,6 +45,7 @@ pub mod extensions {
             "battery/mod.js",
             "web/mod.js",
             "web/events.js",
+            "web/streams.js",
             "web/encoding.js",
             "console/mod.js",
             "console/printer.js",
diff --git a/ext/web/mod.js b/ext/web/mod.js
index 3907b32..52a9be6 100644
--- a/ext/web/mod.js
+++ b/ext/web/mod.js
@@ -1,10 +1,21 @@
 import { TextDecoder, TextEncoder } from "ext:bueno/web/encoding.js";
 import { CustomEvent, Event, EventTarget } from "ext:bueno/web/events.js";
+import {
+	ByteLengthQueuingStrategy,
+	CountQueuingStrategy,
+} from "ext:bueno/web/streams.js";
 
 globalThis.navigator = {};
+
+// Event API
 globalThis.Event = Event;
 globalThis.CustomEvent = CustomEvent;
 globalThis.EventTarget = EventTarget;
 
+// Streams API
+globalThis.ByteLengthQueuingStrategy = ByteLengthQueuingStrategy;
+globalThis.CountQueuingStrategy = CountQueuingStrategy;
+
+// Text Encoding API
 globalThis.TextDecoder = TextDecoder;
 globalThis.TextEncoder = TextEncoder;
diff --git a/ext/web/streams.js b/ext/web/streams.js
new file mode 100644
index 0000000..57b7dfc
--- /dev/null
+++ b/ext/web/streams.js
@@ -0,0 +1,24 @@
+// Ported from https://github.com/whatwg/streams/tree/main/reference-implementation
+
+export class ByteLengthQueuingStrategy {
+	constructor({ highWaterMark }) {
+		this.highWaterMark = highWaterMark;
+	}
+
+	/**
+	 * @param {Uint8Array} chunk
+	 */
+	size(chunk) {
+		return chunk.byteLength;
+	}
+}
+
+export class CountQueuingStrategy {
+	constructor({ highWaterMark }) {
+		this.highWaterMark = highWaterMark;
+	}
+
+	get size() {
+		return 1;
+	}
+}