diff --git a/deno.lock b/deno.lock
index 9286bc4..1b7cd6e 100644
--- a/deno.lock
+++ b/deno.lock
@@ -6,7 +6,7 @@
       "jsr:@cross/runtime@^1.0.0": "jsr:@cross/runtime@1.0.0",
       "jsr:@cross/test@^0.0.9": "jsr:@cross/test@0.0.9",
       "jsr:@std/assert@^1.0.2": "jsr:@std/assert@1.0.2",
-      "jsr:@std/async@^1.0.2": "jsr:@std/async@1.0.2",
+      "jsr:@std/async@^1.0.2": "jsr:@std/async@1.0.3",
       "jsr:@std/internal@^1.0.1": "jsr:@std/internal@1.0.1",
       "npm:@types/node": "npm:@types/node@18.16.19"
     },
@@ -29,8 +29,8 @@
           "jsr:@std/internal@^1.0.1"
         ]
       },
-      "@std/async@1.0.2": {
-        "integrity": "36e7f0f922c843b45df546857d269f01ed4d0406aced2a6639eac325b2435e43"
+      "@std/async@1.0.3": {
+        "integrity": "6ed64678db43451683c6c176a21426a2ccd21ba0269ebb2c36133ede3f165792"
       },
       "@std/internal@1.0.1": {
         "integrity": "6f8c7544d06a11dd256c8d6ba54b11ed870aac6c5aeafff499892662c57673e6"
diff --git a/queue.ts b/queue.ts
index c655a94..59138cb 100644
--- a/queue.ts
+++ b/queue.ts
@@ -17,7 +17,7 @@ import { Notify } from "./notify.ts";
  * assertEquals(await queue.pop(), 3);
  * ```
  */
-export class Queue<T> {
+export class Queue<T extends NonNullable<unknown> | null> {
   #notify = new Notify();
   #items: T[] = [];
 
@@ -52,7 +52,7 @@ export class Queue<T> {
     while (true) {
       signal?.throwIfAborted();
       const value = this.#items.shift();
-      if (value) {
+      if (value !== undefined) {
         return value;
       }
       await this.#notify.notified({ signal });
diff --git a/queue_test.ts b/queue_test.ts
index 9113ead..a91d912 100644
--- a/queue_test.ts
+++ b/queue_test.ts
@@ -57,3 +57,21 @@ test("Queue 'pop' with signal already aborted", async () => {
     "Aborted",
   );
 });
+
+test("Queue with falsy value is accepted", async () => {
+  const q = new Queue<number>();
+  const popper = q.pop();
+  assertEquals(await promiseState(popper), "pending");
+  q.push(0);
+  assertEquals(await promiseState(popper), "fulfilled");
+  assertEquals(await popper, 0);
+});
+
+test("Queue with null is accepted", async () => {
+  const q = new Queue<null>();
+  const popper = q.pop();
+  assertEquals(await promiseState(popper), "pending");
+  q.push(null);
+  assertEquals(await promiseState(popper), "fulfilled");
+  assertEquals(await popper, null);
+});
diff --git a/stack.ts b/stack.ts
index a519a06..01bb33d 100644
--- a/stack.ts
+++ b/stack.ts
@@ -19,7 +19,7 @@ import { Notify } from "./notify.ts";
  *
  * @template T The type of items in the stack.
  */
-export class Stack<T> {
+export class Stack<T extends NonNullable<unknown> | null> {
   #notify = new Notify();
   #items: T[] = [];
 
@@ -56,7 +56,7 @@ export class Stack<T> {
     while (true) {
       signal?.throwIfAborted();
       const value = this.#items.pop();
-      if (value) {
+      if (value !== undefined) {
         return value;
       }
       await this.#notify.notified({ signal });
diff --git a/stack_test.ts b/stack_test.ts
index ef0ffcb..125d4b4 100644
--- a/stack_test.ts
+++ b/stack_test.ts
@@ -57,3 +57,21 @@ test("Stack 'pop' with signal already aborted", async () => {
     "Aborted",
   );
 });
+
+test("Stack with falsy value is accepted", async () => {
+  const q = new Stack<number>();
+  const popper = q.pop();
+  assertEquals(await promiseState(popper), "pending");
+  q.push(0);
+  assertEquals(await promiseState(popper), "fulfilled");
+  assertEquals(await popper, 0);
+});
+
+test("Stack with null is accepted", async () => {
+  const q = new Stack<null>();
+  const popper = q.pop();
+  assertEquals(await promiseState(popper), "pending");
+  q.push(null);
+  assertEquals(await promiseState(popper), "fulfilled");
+  assertEquals(await popper, null);
+});