diff --git a/lib/main.js b/lib/main.js
index 5464be8f..619e1e3b 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -290,9 +290,13 @@ Lambda.prototype._rsync = function (program, src, dest, excludeNodeModules, call
 };
 
 Lambda.prototype._npmInstall = function (program, codeDirectory, callback) {
+  const installOptions = [
+    `--prefix ${codeDirectory}`,
+    process.platform === 'win32' ? `--cwd ${codeDirectory}` : null,
+  ].join(' ');
   var command = program.dockerImage ?
     'docker run --rm -v ' + codeDirectory + ':/var/task ' + program.dockerImage + ' npm -s install --production' :
-    'npm -s install --production --prefix ' + codeDirectory;
+    `npm -s install --production ${installOptions}`;
   exec(command, {
     maxBuffer: maxBufferSize,
     env: process.env