diff --git a/DEPS b/DEPS
index 8d974ffbbf..bf7f15d87a 100644
--- a/DEPS
+++ b/DEPS
@@ -107,7 +107,7 @@ hooks = [
     'action': [
       'python',
       '-c',
-      'import os; os.chdir("src"); os.chdir("electron"); os.system("npm install")',
+      'import os, subprocess; os.chdir(os.path.join("src", "electron")); subprocess.check_call(["python", "script/lib/npm.py", "install"]);',
     ],
   },
   {
@@ -117,7 +117,7 @@ hooks = [
     'action': [
       'python',
       '-c',
-      'import os; os.chdir("src"); os.chdir("electron"); os.chdir("vendor"); os.chdir("boto"); os.system("python setup.py build");',
+      'import os, subprocess; os.chdir(os.path.join("src", "electron", "vendor", "boto")); subprocess.check_call(["python", "setup.py", "build"]);',
     ],
   },
   {
@@ -127,9 +127,9 @@ hooks = [
     'action': [
       'python',
       '-c',
-      'import os; os.chdir("src"); os.chdir("electron"); os.chdir("vendor"); os.chdir("requests"); os.system("python setup.py build");',
+      'import os, subprocess; os.chdir(os.path.join("src", "electron", "vendor", "requests")); subprocess.check_call(["python", "setup.py", "build"]);',
     ],
-  }
+  },
 ]
 
 recursedeps = [
diff --git a/script/lib/npm.py b/script/lib/npm.py
new file mode 100644
index 0000000000..6df6f5f108
--- /dev/null
+++ b/script/lib/npm.py
@@ -0,0 +1,18 @@
+import subprocess
+import sys
+
+
+def npm(*npm_args):
+    call_args = [__get_executable_name()] + list(npm_args)
+    subprocess.check_call(call_args)
+
+
+def __get_executable_name():
+    executable = 'npm'
+    if sys.platform == 'win32':
+        executable += '.cmd'
+    return executable
+
+
+if __name__ == '__main__':
+    npm(*sys.argv[1:])