diff --git a/.gitignore b/.gitignore
index c15ce30e5b..15b975b8de 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,12 +1,9 @@
 # build
 /out/
 *.pyc
-
+gclient_config.py_entries
 # npm deps
 node_modules
 
-# third party deps
-/third_party/
-
 # RLS generated files
-/target/
\ No newline at end of file
+/target/
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000..82935121a8
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "third_party"]
+	path = third_party
+	url = https://github.com/ry/deno_third_party.git
diff --git a/.travis.yml b/.travis.yml
index f0aa43c6c6..4549b5bfdc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,6 @@ branches:
 cache:
   ccache: true
   directories:
-   - third_party/node_modules/
    - $DEPOT_TOOLS_PATH
    - $BUILD_PATH
 env:
@@ -28,7 +27,10 @@ install:
  - curl -sSf https://sh.rustup.rs | sh -s -- -y
  - export PATH=$HOME/.cargo/bin:$PATH
  - rustc --version
- - ./tools/build_third_party.py
+ # TODO(ry) Do not depend on run_hooks because it calls
+ # //third_party/depot_tools/download_from_google_storage.py
+ # Use git lfs and combine run_hooks with build_third_party?
+ - ./tools/run_hooks.py
  # ccache needs the custom LLVM to be in PATH and other variables.
  - export PATH=`pwd`/third_party/llvm-build/Release+Asserts/bin:$PATH
  - export CCACHE_CPP2=yes
diff --git a/README.md b/README.md
index 6c4af1de11..2363f5d7aa 100644
--- a/README.md
+++ b/README.md
@@ -56,41 +56,40 @@ Roadmap is [here](https://github.com/ry/deno/blob/master/Roadmap.md).
 
 Also see this presentation: http://tinyclouds.org/jsconf2018.pdf
 
-### Github Noise
-
 I am excited about all the interest in this project. However, do understand that this
 is very much a non-functional prototype. There's a huge amount of heavy lifting to do.
 Unless you are participating in that, please maintain radio silence on github. This
 includes submitting trivial PRs (like improving README build instructions).
 
-## Compile instructions
+## Build instructions
 
-Get [Depot Tools](http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up) and make sure it's in your path.
+To ensure reproducable builds, Deno has most of its dependencies in a git
+submodule. However, you need
+[rustc](https://www.rust-lang.org/en-US/install.html) installed separately.
 
-You need [yarn](https://yarnpkg.com/lang/en/docs/install/) installed.
+You probably want
+[ccache](https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/ccache)
+installed too.
 
-You need [rust](https://www.rust-lang.org/en-US/install.html) installed.
+To build:
 
-You might want  [ccache](https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/ccache) installed.
+    # Fetch deps.
+    git clone --recurse-submodules https://github.com/ry/deno.git
+    cd deno
+    ./tools/run_hooks.py
 
-Fetch the third party dependencies.
+    # Configure
+    ./third_party/depot_tools/gn gen out/default
+    ./third_party/depot_tools/gn gen out/release --args='cc_wrapper="ccache" is_official_build=true'
+    ./third_party/depot_tools/gn gen out/debug --args='cc_wrapper="ccache" is_debug=true '
 
-    ./tools/build_third_party.py
-
-Generate ninja files.
-
-    gn gen out/Default
-    gn gen out/Release --args='cc_wrapper="ccache" is_official_build=true'
-    gn gen out/Debug --args='cc_wrapper="ccache" is_debug=true '
-
-Then build with ninja (will take a while to complete):
-
-    ninja -C out/Debug/ deno
+    # Build
+    ./third_party/depot_tools/ninja -C out/default/ deno
 
 Other useful commands:
 
-    gn args out/Debug/ --list
-    gn args out/Debug/
-    gn desc out/Debug/ :deno
-    gn help
+    ./third_party/depot_tools/gn args out/default/ --list
+    ./third_party/depot_tools/gn args out/default/
+    ./third_party/depot_tools/gn desc out/default/ :deno
+    ./third_party/depot_tools/gn help
 
diff --git a/gclient_config.py b/gclient_config.py
index 32bfcc425f..e20d7dce69 100644
--- a/gclient_config.py
+++ b/gclient_config.py
@@ -17,6 +17,11 @@ solutions = [{
         'v8/test/test262/harness': None,
         'v8/tools/luci-go': None
     }
+}, {
+    'url':
+    'https://chromium.googlesource.com/chromium/tools/depot_tools@40bacee96a94600ad2179d69a8025469d119960f',
+    'name':
+    'depot_tools'
 }, {
     'url':
     'https://chromium.googlesource.com/chromium/src/third_party/zlib@39b4a6260702da4c089eca57136abf40a39667e9',
diff --git a/third_party b/third_party
new file mode 160000
index 0000000000..2dde8457b0
--- /dev/null
+++ b/third_party
@@ -0,0 +1 @@
+Subproject commit 2dde8457b037a399f07106ccfc34382a80c469bb
diff --git a/tools/build_third_party.py b/tools/build_third_party.py
index e46c8ddd1f..474fcbfd22 100755
--- a/tools/build_third_party.py
+++ b/tools/build_third_party.py
@@ -1,15 +1,8 @@
 #!/usr/bin/env python
-# This script generates the third party dependencies of deno.
-# - Get Depot Tools and make sure it's in your path.
-#   http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up
-# - You need yarn installed as well.
-#   https://yarnpkg.com/lang/en/docs/install/
-# Use //gclient_config.py to modify the git deps.
-# Use //js/package.json to modify the npm deps.
+# Only run this script if you are changing Deno's dependencies.
 
 import os
 from os.path import join
-import subprocess
 from util import run, remove_and_symlink
 
 root_path = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
@@ -20,14 +13,23 @@ try:
 except:
     pass
 os.chdir(third_party_path)
-remove_and_symlink(join("..", "gclient_config.py"), ".gclient")
-remove_and_symlink(join("..", "package.json"), "package.json")
-remove_and_symlink(join("..", "yarn.lock"), "yarn.lock")
-remove_and_symlink(join("v8", "third_party", "googletest"), "googletest")
-remove_and_symlink(join("v8", "third_party", "jinja2"), "jinja2")
-remove_and_symlink(join("v8", "third_party", "llvm-build"), "llvm-build")
-remove_and_symlink(join("v8", "third_party", "markupsafe"), "markupsafe")
-run(["gclient", "sync", "--shallow", "--no-history"])
+
+# Run yarn to install JavaScript dependencies.
+remove_and_symlink("../package.json", "package.json")
+remove_and_symlink("../yarn.lock", "yarn.lock")
 run(["yarn"])
-run(["cargo", "fetch", "--manifest-path=../Cargo.toml"],
+# Run cargo to install Rust dependencies.
+run(["cargo", "fetch", "--manifest-path=" + root_path + "/Cargo.toml"],
     envs={'CARGO_HOME': third_party_path + '/rust_crates'})
+# Run gclient to install other dependencies.
+run(["gclient", "sync", "--reset", "--shallow", "--no-history", "--nohooks"],
+    envs={'GCLIENT_FILE': root_path + "/gclient_config.py"})
+# TODO(ry) Is it possible to remove these symlinks?
+remove_and_symlink("v8/third_party/googletest", "googletest")
+remove_and_symlink("v8/third_party/jinja2", "jinja2")
+remove_and_symlink("v8/third_party/llvm-build", "llvm-build")
+remove_and_symlink("v8/third_party/markupsafe", "markupsafe")
+
+# To update the deno_third_party git repo after running this, try the following:
+# cd third_party
+# find . -type f | grep -v "\.git" | xargs -I% git add -f --no-warn-embedded-repo "%"
diff --git a/tools/run_hooks.py b/tools/run_hooks.py
new file mode 100755
index 0000000000..2ec671186d
--- /dev/null
+++ b/tools/run_hooks.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+import os
+import sys
+from util import run
+
+root_path = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+third_party_path = os.path.join(root_path, "third_party")
+depot_tools_path = os.path.join(third_party_path, "depot_tools")
+os.chdir(root_path)
+
+
+def download(fn):
+    run([
+        os.path.join(depot_tools_path + '/download_from_google_storage.py'),
+        '--no_resume', '--platform=' + sys.platform, '--no_auth', '--bucket',
+        'chromium-gn', '-s',
+        os.path.join(root_path, fn)
+    ],
+        quiet=True)
+
+
+if sys.platform == 'win32':
+    download("third_party/v8/buildtools/win/gn.exe.sha1")
+elif sys.platform == 'darwin':
+    download("third_party/v8/buildtools/mac/gn.sha1")
+elif sys.platform.startswith('linux'):
+    download("third_party/v8/buildtools/linux64/gn.sha1")
+run(['python', 'third_party/v8/tools/clang/scripts/update.py', '--if-needed'],
+    quiet=True)