diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index c79007ebdd..972405680f 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -130,6 +130,16 @@ declare namespace Deno {
      * Requires `allow-env` permission. */
     set(key: string, value: string): void;
 
+    /** Delete the value of an environment variable.
+     *
+     * ```ts
+     * Deno.env.set("SOME_VAR", "Value"));
+     * Deno.env.delete("SOME_VAR");  // outputs "Undefined"
+     * ```
+     *
+     * Requires `allow-env` permission. */
+    delete(key: string): void;
+
     /** Returns a snapshot of the environment variables at invocation.
      *
      * ```ts
diff --git a/cli/js/ops/os.ts b/cli/js/ops/os.ts
index 30aa6d0d48..e63d8b3583 100644
--- a/cli/js/ops/os.ts
+++ b/cli/js/ops/os.ts
@@ -27,12 +27,17 @@ function getEnv(key: string): string | undefined {
   return sendSync("op_get_env", { key })[0];
 }
 
+function deleteEnv(key: string): void {
+  sendSync("op_delete_env", { key });
+}
+
 export const env = {
   get: getEnv,
   toObject(): { [key: string]: string } {
     return sendSync("op_env");
   },
   set: setEnv,
+  delete: deleteEnv,
 };
 
 type DirKind =
diff --git a/cli/ops/os.rs b/cli/ops/os.rs
index 36cd99577d..ab7ed28766 100644
--- a/cli/ops/os.rs
+++ b/cli/ops/os.rs
@@ -15,6 +15,7 @@ pub fn init(i: &mut CoreIsolate, s: &State) {
   i.register_op("op_exec_path", s.stateful_json_op(op_exec_path));
   i.register_op("op_set_env", s.stateful_json_op(op_set_env));
   i.register_op("op_get_env", s.stateful_json_op(op_get_env));
+  i.register_op("op_delete_env", s.stateful_json_op(op_delete_env));
   i.register_op("op_get_dir", s.stateful_json_op(op_get_dir));
   i.register_op("op_hostname", s.stateful_json_op(op_hostname));
   i.register_op("op_loadavg", s.stateful_json_op(op_loadavg));
@@ -137,6 +138,22 @@ fn op_get_env(
   Ok(JsonOp::Sync(r))
 }
 
+#[derive(Deserialize)]
+struct DeleteEnv {
+  key: String,
+}
+
+fn op_delete_env(
+  state: &State,
+  args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<JsonOp, OpError> {
+  let args: DeleteEnv = serde_json::from_value(args)?;
+  state.check_env()?;
+  env::remove_var(args.key);
+  Ok(JsonOp::Sync(json!({})))
+}
+
 #[derive(Deserialize)]
 struct Exit {
   code: i32,
diff --git a/cli/tests/unit/os_test.ts b/cli/tests/unit/os_test.ts
index 72c88b0e10..9698692c79 100644
--- a/cli/tests/unit/os_test.ts
+++ b/cli/tests/unit/os_test.ts
@@ -20,6 +20,13 @@ unitTest({ perms: { env: true } }, function envNotFound(): void {
   assertEquals(r, undefined);
 });
 
+unitTest({ perms: { env: true } }, function deleteEnv(): void {
+  Deno.env.set("TEST_VAR", "A");
+  assertEquals(Deno.env.get("TEST_VAR"), "A");
+  assertEquals(Deno.env.delete("TEST_VAR"), undefined);
+  assertEquals(Deno.env.get("TEST_VAR"), undefined);
+});
+
 unitTest(function envPermissionDenied1(): void {
   let err;
   try {