diff --git a/Cargo.lock b/Cargo.lock
index b53197223e..20e94e0c9d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -296,6 +296,7 @@ dependencies = [
  "serde_derive 1.0.100 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
  "source-map-mappings 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sys-info 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1378,6 +1379,15 @@ dependencies = [
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sys-info"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.1.0"
@@ -2103,6 +2113,7 @@ dependencies = [
 "checksum syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)" = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
 "checksum syn 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "66850e97125af79138385e9b88339cbcd037e3f28ceab8c5ad98e64f0f1f80bf"
 "checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
+"checksum sys-info 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)" = "0079fe39cec2c8215e21b0bc4ccec9031004c160b88358f531b601e96b77f0df"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum termcolor 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "96d6098003bde162e4277c70665bd87c326f5a0c3f3fbfb285787fa482d54e6e"
 "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 4cb59f1712..8894980d7b 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -45,6 +45,7 @@ serde = { version = "1.0.100", features = ["derive"] }
 serde_derive = "1.0.100"
 serde_json = { version = "1.0.40", features = [ "preserve_order" ] }
 source-map-mappings = "0.5.0"
+sys-info = "0.5.8"
 tempfile = "3.1.0"
 termcolor = "1.0.5"
 tokio = "0.1.22"
diff --git a/cli/ops/mod.rs b/cli/ops/mod.rs
index ea71fee9fa..ab318438f0 100644
--- a/cli/ops/mod.rs
+++ b/cli/ops/mod.rs
@@ -83,6 +83,7 @@ pub const OP_MAKE_TEMP_DIR: OpId = 55;
 pub const OP_CWD: OpId = 56;
 pub const OP_FETCH_ASSET: OpId = 57;
 pub const OP_DIAL_TLS: OpId = 58;
+pub const OP_HOSTNAME: OpId = 59;
 
 pub fn dispatch(
   state: &ThreadSafeState,
@@ -305,6 +306,9 @@ pub fn dispatch(
     OP_DIAL_TLS => {
       dispatch_json::dispatch(tls::op_dial_tls, state, control, zero_copy)
     }
+    OP_HOSTNAME => {
+      dispatch_json::dispatch(os::op_hostname, state, control, zero_copy)
+    }
     _ => panic!("bad op_id"),
   };
 
diff --git a/cli/ops/os.rs b/cli/ops/os.rs
index d033dc9c31..770af404c7 100644
--- a/cli/ops/os.rs
+++ b/cli/ops/os.rs
@@ -9,6 +9,7 @@ use deno::*;
 use log;
 use std::collections::HashMap;
 use std::env;
+use sys_info;
 use url::Url;
 
 /// BUILD_OS and BUILD_ARCH match the values in Deno.build. See js/build.ts.
@@ -126,3 +127,13 @@ pub fn op_is_tty(
     "stderr": atty::is(atty::Stream::Stderr),
   })))
 }
+
+pub fn op_hostname(
+  state: &ThreadSafeState,
+  _args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  state.check_env()?;
+  let hostname = sys_info::hostname().unwrap_or_else(|_| "".to_owned());
+  Ok(JsonOp::Sync(json!(hostname)))
+}
diff --git a/js/deno.ts b/js/deno.ts
index 916b7471a8..511e4f0ecc 100644
--- a/js/deno.ts
+++ b/js/deno.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 
 // Public deno module.
-export { env, exit, isTTY, execPath, homeDir } from "./os.ts";
+export { env, exit, isTTY, execPath, homeDir, hostname } from "./os.ts";
 export { chdir, cwd } from "./dir.ts";
 export {
   File,
diff --git a/js/dispatch.ts b/js/dispatch.ts
index b5116d68a3..5dfec625fa 100644
--- a/js/dispatch.ts
+++ b/js/dispatch.ts
@@ -61,6 +61,7 @@ export const OP_MAKE_TEMP_DIR = 55;
 export const OP_CWD = 56;
 export const OP_FETCH_ASSET = 57;
 export const OP_DIAL_TLS = 58;
+export const OP_HOSTNAME = 59;
 
 export function asyncMsgFromRust(opId: number, ui8: Uint8Array): void {
   switch (opId) {
diff --git a/js/lib.deno_runtime.d.ts b/js/lib.deno_runtime.d.ts
index 36e49c9c23..8eb46b410e 100644
--- a/js/lib.deno_runtime.d.ts
+++ b/js/lib.deno_runtime.d.ts
@@ -22,6 +22,12 @@ declare namespace Deno {
     stdout: boolean;
     stderr: boolean;
   };
+  /** Get the hostname.
+   * Requires the `--allow-env` flag.
+   *
+   *       console.log(Deno.hostname());
+   */
+  export function hostname(): string;
   /** Exit the Deno process with optional exit code. */
   export function exit(code?: number): never;
   /** Returns a snapshot of the environment variables at invocation. Mutating a
diff --git a/js/os.ts b/js/os.ts
index 0e4d86917c..a26f57cb39 100644
--- a/js/os.ts
+++ b/js/os.ts
@@ -18,6 +18,15 @@ export function isTTY(): { stdin: boolean; stdout: boolean; stderr: boolean } {
   return sendSync(dispatch.OP_IS_TTY);
 }
 
+/** Get the hostname.
+ * Requires the `--allow-env` flag.
+ *
+ *       console.log(Deno.hostname());
+ */
+export function hostname(): string {
+  return sendSync(dispatch.OP_HOSTNAME);
+}
+
 /** Exit the Deno process with optional exit code. */
 export function exit(code = 0): never {
   sendSync(dispatch.OP_EXIT, { code });
diff --git a/js/os_test.ts b/js/os_test.ts
index 28c8b6a0be..ad37726313 100644
--- a/js/os_test.ts
+++ b/js/os_test.ts
@@ -70,3 +70,19 @@ testPerm({ env: false }, function execPathPerm(): void {
   }
   assert(caughtError);
 });
+
+testPerm({ env: true }, function hostnameDir(): void {
+  assertNotEquals(Deno.hostname(), "");
+});
+
+testPerm({ env: false }, function hostnamePerm(): void {
+  let caughtError = false;
+  try {
+    Deno.hostname();
+  } catch (err) {
+    caughtError = true;
+    assertEquals(err.kind, Deno.ErrorKind.PermissionDenied);
+    assertEquals(err.name, "PermissionDenied");
+  }
+  assert(caughtError);
+});