diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5245f42fc1..699bc6516f3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+* Install script falls back to `npm install` ([#319](https://github.com/evanw/esbuild/issues/319))
+
+    The `esbuild` package has a post-install script that downloads the esbuild binary. However, this will fail if `registry.npmjs.org` (or the configured custom npm registry) is inaccessible.
+
+    This release adds an additional fallback for when the download fails. It tries to use the `npm install` command to download the esbuild binary instead. This handles situations where users have either configured npm with a proxy or have a custom command in their path called `npm`.
+
 ## 0.6.17
 
 * Add a download cache to the install script
diff --git a/lib/install.ts b/lib/install.ts
index 6edc974b87b..c5b6ae45b89 100644
--- a/lib/install.ts
+++ b/lib/install.ts
@@ -4,6 +4,7 @@ import url = require('url');
 import path = require('path');
 import zlib = require('zlib');
 import https = require('https');
+import child_process = require('child_process');
 
 const version = require('./package.json').version;
 const binPath = path.join(__dirname, 'bin', 'esbuild');
@@ -40,6 +41,24 @@ async function installBinaryFromPackage(name: string, fromPath: string, toPath:
   let urls = [`https://${officialRegistry}/${name}/-/${name}-${version}.tgz`];
   let debug = false;
 
+  let finishInstall = (buffer: Buffer): void => {
+    // Write out the binary executable that was extracted from the package
+    fs.writeFileSync(toPath, buffer, { mode: 0o755 });
+
+    // Mark the operation as successful so this script is idempotent
+    fs.writeFileSync(stampPath, '');
+
+    // Also try to cache the file to speed up future installs
+    try {
+      fs.mkdirSync(path.dirname(cachePath), { recursive: true });
+      fs.copyFileSync(toPath, cachePath);
+      cleanCacheLRU(cachePath);
+    } catch {
+    }
+
+    if (debug) console.error(`Install successful`);
+  };
+
   // Try downloading from a custom registry first if one is configured
   try {
     let env = url.parse(process.env.npm_config_registry || '');
@@ -57,38 +76,31 @@ async function installBinaryFromPackage(name: string, fromPath: string, toPath:
   } catch {
   }
 
+  // Try each registry URL in succession
   for (let url of urls) {
     let tryText = `Trying to download ${JSON.stringify(url)}`;
-    if (debug) console.error(tryText);
-
     try {
-      let buffer = extractFileFromTarGzip(await fetch(url), fromPath);
-      if (debug) console.error(`Install successful`);
-
-      // Write out the binary executable that was extracted from the package
-      fs.writeFileSync(toPath, buffer, { mode: 0o755 });
-
-      // Mark the operation as successful so this script is idempotent
-      fs.writeFileSync(stampPath, '');
-
-      // Also try to cache the file to speed up future installs
-      try {
-        fs.mkdirSync(path.dirname(cachePath), { recursive: true });
-        fs.copyFileSync(toPath, cachePath);
-        await cleanCacheLRU(cachePath);
-      } catch {
-      }
-
+      if (debug) console.error(tryText);
+      finishInstall(extractFileFromTarGzip(await fetch(url), fromPath));
       return;
-    }
-
-    catch (err) {
+    } catch (err) {
       if (!debug) console.error(tryText);
       console.error(`Failed to download ${JSON.stringify(url)}: ${err && err.message || err}`);
       debug = true;
     }
   }
 
+  // If all of this fails, try using npm install instead. This is an attempt to
+  // work around users that cannot send normal HTTP requests. For example, they
+  // may have blocked registry.npmjs.org and configured a HTTPS proxy instead.
+  try {
+    console.log(`Trying to install "${name}" using npm`)
+    finishInstall(installUsingNPM(name, fromPath));
+    return;
+  } catch (err) {
+    console.error(`Failed to install "${name}" using npm: ${err && err.message || err}`);
+  }
+
   console.error(`Install unsuccessful`);
   process.exit(1);
 }
@@ -101,23 +113,27 @@ function getCachePath(name: string): string {
   return path.join(home, '.cache', ...common);
 }
 
-async function cleanCacheLRU(fileToKeep: string): Promise<void> {
+function cleanCacheLRU(fileToKeep: string): void {
   // Gather all entries in the cache
   const dir = path.dirname(fileToKeep);
   const entries: { path: string, mtime: Date }[] = [];
-  await Promise.all(fs.readdirSync(dir).map(entry => new Promise(resolve => {
+  for (const entry of fs.readdirSync(dir)) {
     const entryPath = path.join(dir, entry);
-    fs.stat(entryPath, (err, stats) => {
-      if (!err) entries.push({ path: entryPath, mtime: stats.mtime });
-      resolve();
-    });
-  })));
+    try {
+      const stats = fs.statSync(entryPath);
+      entries.push({ path: entryPath, mtime: stats.mtime });
+    } catch {
+    }
+  }
 
   // Only keep the most recent entries
   entries.sort((a, b) => +b.mtime - +a.mtime);
-  await Promise.all(entries.slice(5).map(entry => new Promise(resolve => {
-    fs.unlink(entry.path, resolve);
-  })));
+  for (const entry of entries.slice(5)) {
+    try {
+      fs.unlinkSync(entry.path);
+    } catch {
+    }
+  }
 }
 
 function fetch(url: string): Promise<Buffer> {
@@ -142,6 +158,7 @@ function extractFileFromTarGzip(buffer: Buffer, file: string): Buffer {
   }
   let str = (i: number, n: number) => String.fromCharCode(...buffer.subarray(i, i + n)).replace(/\0.*$/, '');
   let offset = 0;
+  file = `package/${file}`;
   while (offset < buffer.length) {
     let name = str(offset, 100);
     let size = parseInt(str(offset + 124, 12), 8);
@@ -154,12 +171,44 @@ function extractFileFromTarGzip(buffer: Buffer, file: string): Buffer {
   throw new Error(`Could not find ${JSON.stringify(file)} in archive`);
 }
 
+function installUsingNPM(name: string, file: string): Buffer {
+  const installDir = path.join(__dirname, '.install');
+  fs.mkdirSync(installDir);
+  fs.writeFileSync(path.join(installDir, 'package.json'), '{}');
+
+  // Erase "npm_config_global" so that "npm install --global esbuild" works.
+  // Otherwise this nested "npm install" will also be global, and the install
+  // will deadlock waiting for the global installation lock.
+  const env = { ...process.env, npm_config_global: undefined };
+
+  child_process.execSync(`npm install --loglevel=error --prefer-offline --no-audit --progress=false ${name}@${version}`,
+    { cwd: installDir, stdio: 'inherit', env });
+  const buffer = fs.readFileSync(path.join(installDir, 'node_modules', name, file));
+  removeRecursive(installDir);
+  return buffer;
+}
+
+function removeRecursive(dir: string): void {
+  for (const entry of fs.readdirSync(dir)) {
+    const entryPath = path.join(dir, entry);
+    let stats;
+    try {
+      stats = fs.lstatSync(entryPath);
+    } catch (e) {
+      continue; // Guard against https://github.com/nodejs/node/issues/4760
+    }
+    if (stats.isDirectory()) removeRecursive(entryPath);
+    else fs.unlinkSync(entryPath);
+  }
+  fs.rmdirSync(dir);
+}
+
 function installOnUnix(name: string): void {
   if (process.env.ESBUILD_BIN_PATH_FOR_TESTS) {
     fs.unlinkSync(binPath);
     fs.symlinkSync(process.env.ESBUILD_BIN_PATH_FOR_TESTS, binPath);
   } else {
-    installBinaryFromPackage(name, 'package/bin/esbuild', binPath)
+    installBinaryFromPackage(name, 'bin/esbuild', binPath)
       .catch(e => setImmediate(() => { throw e; }));
   }
 }
@@ -177,7 +226,7 @@ child_process.spawnSync(esbuild_exe, process.argv.slice(2), { stdio: 'inherit' }
   if (process.env.ESBUILD_BIN_PATH_FOR_TESTS) {
     fs.copyFileSync(process.env.ESBUILD_BIN_PATH_FOR_TESTS, exePath);
   } else {
-    installBinaryFromPackage(name, 'package/esbuild.exe', exePath)
+    installBinaryFromPackage(name, 'esbuild.exe', exePath)
       .catch(e => setImmediate(() => { throw e; }));
   }
 }