diff --git a/lib/commands/cache-clean.js b/lib/commands/cache-clean.js
index f2081491..0db8df96 100644
--- a/lib/commands/cache-clean.js
+++ b/lib/commands/cache-clean.js
@@ -70,3 +70,13 @@ module.exports.line = function (argv) {
   if (options.help) return help('cache-clean');
   return module.exports(pkgs, options);
 };
+
+module.exports.completion = function (opts, cb) {
+  glob('./*', { cwd: config.cache }, function (err, dirs) {
+    if (err) return cb(err);
+    dirs = dirs.map(function (dir) {
+      return dir.replace(/^\.\//, '');
+    });
+    cb(null, dirs);
+  });
+};
diff --git a/lib/commands/completion.js b/lib/commands/completion.js
new file mode 100644
index 00000000..10121e0d
--- /dev/null
+++ b/lib/commands/completion.js
@@ -0,0 +1,102 @@
+// ==========================================
+// BOWER: Completion API
+// ==========================================
+// Copyright 2012 Twitter, Inc
+// Licensed under The MIT License
+// http://opensource.org/licenses/MIT
+// ==========================================
+var Emitter  = require('events').EventEmitter;
+var path     = require('path');
+var nopt     = require('nopt');
+var mkdirp   = require('mkdirp');
+
+var template = require('../util/template');
+var complete = require('../util/completion');
+var config   = require('../core/config');
+var help     = require('./help');
+
+var optionTypes = { help: Boolean };
+var shorthand   = { 'h': ['--help'] };
+
+module.exports = function (argv, env) {
+  env = env || process.env;
+
+  var emitter = new Emitter;
+  var commands = require('../commands');
+
+  // top level flags
+  var flags = ['--no-color', '--help', '--version'];
+
+  var done = function done() {
+    process.nextTick(function () {
+      emitter.emit('end');
+    });
+
+    return emitter;
+  };
+
+  // if the COMP_* isn't in the env, then just dump the script.
+  if (!env.COMP_CWORD) {
+    template('completion').on('data', emitter.emit.bind(emitter, 'end'));
+    return emitter;
+  }
+
+  // parse environment and arguments, returns a hash of completion config.
+  var opts = complete(argv, env);
+
+  // if only one word, complete the list of command or top level flags
+  if (opts.w === 1) {
+    if (opts.word.charAt(0) === '-') complete.log(flags, opts);
+    else complete.log(Object.keys(commands), opts);
+    return done();
+  }
+
+  // try to find the bower command. first thing after all the configs.
+  var parsed = opts.conf = nopt({}, {}, opts.partialWords, 0);
+  var cmd = parsed.argv.remain[0];
+
+  // unable to find a command, complete the lisf of commands
+  if (!cmd) {
+    complete.log(Object.keys(commands), opts);
+    return done();
+  }
+
+  // if words[0] is a bower command, then complete on it.
+  cmd = commands[cmd];
+
+  if (cmd && cmd.completion) {
+    // prior to that, ensure the completion cache directory is created first
+    mkdirp(path.join(config.completion), function (err) {
+      if (err) return emitter.emit('error', err);
+      cmd.completion(opts, function (err, data) {
+        if (err) return emitter.emit('error', err);
+
+        // completing options, then append top level flags
+        if (opts.word.charAt(0) === '-') data = data.concat(flags);
+
+        complete.log(data, opts);
+
+        done();
+      });
+    });
+
+    return emitter;
+  }
+
+  // otherwise, do nothing
+  return emitter;
+};
+
+module.exports.line = function (argv) {
+  var emitter  = new Emitter;
+  var options  = nopt(optionTypes, shorthand, argv);
+
+  if (options.help) return help('completion');
+
+  module.exports(options.argv.remain.slice(2), process.env)
+    .on('data', emitter.emit.bind(emitter, 'data'))
+    .on('error', emitter.emit.bind(emitter, 'error'))
+    .on('end', emitter.emit.bind(emitter, 'end'));
+
+  return emitter;
+};
diff --git a/lib/commands/help.js b/lib/commands/help.js
index e578ac0a..98cd8ba7 100644
--- a/lib/commands/help.js
+++ b/lib/commands/help.js
@@ -29,4 +29,8 @@ module.exports.line = function (argv) {
   var options  = nopt({}, {}, argv);
   var paths    = options.argv.remain.slice(1);
   return module.exports(paths[0]);
-};
\ No newline at end of file
+};
+
+module.exports.completion = function (opts, cb) {
+  return cb(null, Object.keys(require('../commands')));
+};
diff --git a/lib/commands/index.js b/lib/commands/index.js
index 405eb3d0..111e2dad 100644
--- a/lib/commands/index.js
+++ b/lib/commands/index.js
@@ -18,5 +18,6 @@ module.exports = {
   'info':        require('./info'),
   'register':    require('./register'),
   'search':      require('./search'),
-  'cache-clean': require('./cache-clean')
-};
\ No newline at end of file
+  'cache-clean': require('./cache-clean'),
+  'completion':  require('./completion')
+};
diff --git a/lib/commands/info.js b/lib/commands/info.js
index 86274e66..84e0a37a 100644
--- a/lib/commands/info.js
+++ b/lib/commands/info.js
@@ -10,6 +10,7 @@ var nopt     = require('nopt');
 
 var template = require('../util/template');
 var source   = require('../core/source');
+var install  = require('./install');
 var help     = require('./help');
 
 var optionTypes = { help: Boolean };
@@ -42,4 +43,6 @@ module.exports.line = function (argv) {
     });
 
   return emitter;
-};
\ No newline at end of file
+};
+
+module.exports.completion = install.completion;
diff --git a/lib/commands/install.js b/lib/commands/install.js
index 9d40b6ec..65dbd9dd 100644
--- a/lib/commands/install.js
+++ b/lib/commands/install.js
@@ -13,8 +13,12 @@
 
 var Emitter = require('events').EventEmitter;
 var nopt    = require('nopt');
+var fs      = require('fs');
+var path    = require('path');
 
 var Manager = require('../core/manager');
+var config  = require('../core/config');
+var source  = require('../core/source');
 var save    = require('../util/save');
 var help    = require('./help');
 
@@ -43,3 +47,36 @@ module.exports.line = function (argv) {
   if (options.help) return help('install');
   return module.exports(paths, options);
 };
+
+module.exports.completion = function (opts, cb) {
+  var word = opts.word;
+
+  // completing options?
+  if (opts.words[0] === 'install' && word.charAt(0) === '-') {
+    return cb(null, Object.keys(optionTypes).map(function (option) {
+      return '--' + option;
+    }));
+  }
+
+  var cache = path.join(config.completion, 'install.json');
+  var done = function done(err, results) {
+    if (err) return cb(err);
+    var names = results.map(function (pkg) {
+      return pkg.name;
+    });
+
+    return cb(null, names);
+  };
+
+  fs.readFile(cache, function (err, body) {
+    if (!err) return done(null, JSON.parse(body));
+
+    // expected error, do the first request and cache the results
+    source.all(function (err, results) {
+      if (err) return cb(err);
+      fs.writeFile(cache, JSON.stringify(results, null, 2), function (err) {
+        done(err, results);
+      });
+    });
+  });
+};
diff --git a/lib/commands/link.js b/lib/commands/link.js
index 4808b4b6..0f65afd9 100644
--- a/lib/commands/link.js
+++ b/lib/commands/link.js
@@ -108,4 +108,12 @@ module.exports.line = function (argv) {
 
   if (options.help) return help('link');
   return module.exports(name);
-};
\ No newline at end of file
+};
+
+module.exports.completion = function (opts, cb) {
+  fs.readdir(config.links, function (err, dirs) {
+    // ignore ENOENT, ~/.bower/links not created yet
+    if (err && err.code === 'ENOENT') return cb(null, []);
+    cb(err, dirs);
+  });
+};
diff --git a/lib/commands/list.js b/lib/commands/list.js
index 47c5f5c1..8c655889 100644
--- a/lib/commands/list.js
+++ b/lib/commands/list.js
@@ -177,4 +177,14 @@ module.exports.line = function (argv) {
   var options = nopt(optionTypes, shorthand, argv);
   if (options.help) return help('list');
   return module.exports(options);
-};
\ No newline at end of file
+};
+
+module.exports.completion = function (opts, cb) {
+  if (!/^-/.test(opts.word)) return cb(null, []);
+
+  var results = Object.keys(optionTypes).map(function (option) {
+    return '--' + option;
+  });
+
+  cb(null, results);
+};
diff --git a/lib/commands/lookup.js b/lib/commands/lookup.js
index ac60d46f..375583e0 100644
--- a/lib/commands/lookup.js
+++ b/lib/commands/lookup.js
@@ -11,6 +11,7 @@ var nopt     = require('nopt');
 
 var template = require('../util/template');
 var source   = require('../core/source');
+var install  = require('./install');
 var help     = require('./help');
 
 var optionTypes = { help: Boolean };
@@ -46,4 +47,6 @@ module.exports.line = function (argv) {
 
   if (options.help || !names.length) return help('lookup');
   return module.exports(names[0]);
-};
\ No newline at end of file
+};
+
+module.exports.completion = install.completion;
diff --git a/lib/commands/search.js b/lib/commands/search.js
index 4d4f170b..f1cd7d82 100644
--- a/lib/commands/search.js
+++ b/lib/commands/search.js
@@ -11,6 +11,7 @@ var nopt     = require('nopt');
 
 var template = require('../util/template');
 var source   = require('../core/source');
+var install  = require('./install');
 var help     = require('./help');
 
 var optionTypes = { help: Boolean };
@@ -46,4 +47,6 @@ module.exports.line = function (argv) {
 
   if (options.help) return help('search');
   return module.exports(names[0]);
-};
\ No newline at end of file
+};
+
+module.exports.completion = install.completion;
diff --git a/lib/commands/uninstall.js b/lib/commands/uninstall.js
index 707e595e..1cb5d151 100644
--- a/lib/commands/uninstall.js
+++ b/lib/commands/uninstall.js
@@ -149,4 +149,21 @@ module.exports.line = function (argv) {
   var names = options.argv.remain.slice(1);
 
   return module.exports(names, options);
-};
\ No newline at end of file
+};
+
+module.exports.completion = function (opts, cb) {
+  var word = opts.word;
+
+  // completing options?
+  if (opts.words[0] === 'uninstall' && word.charAt(0) === '-') {
+    return cb(null, Object.keys(optionTypes).map(function (option) {
+      return '--' + option;
+    }));
+  }
+
+  fs.readdir(config.directory, function (err, dirs) {
+    // ignore ENOENT, ./components not created yet
+    if (err && err.code === 'ENOENT') return cb(null, []);
+    cb(err, dirs);
+  });
+};
diff --git a/lib/commands/update.js b/lib/commands/update.js
index 39287299..1098831c 100644
--- a/lib/commands/update.js
+++ b/lib/commands/update.js
@@ -11,8 +11,9 @@ var async   = require('async');
 var nopt    = require('nopt');
 var _       = require('lodash');
 
-var Manager = require('../core/manager');
-var help    = require('./help');
+var Manager   = require('../core/manager');
+var help      = require('./help');
+var uninstall = require('./uninstall');
 
 var shorthand   = { 'h': ['--help'], 'f': ['--force'] };
 var optionTypes = { help: Boolean, force: Boolean };
@@ -75,4 +76,6 @@ module.exports.line = function (argv) {
 
   var paths = options.argv.remain.slice(1);
   return module.exports(paths, options);
-};
\ No newline at end of file
+};
+
+module.exports.completion = uninstall.completion;
diff --git a/lib/core/config.js b/lib/core/config.js
index f305356e..7dfe7050 100644
--- a/lib/core/config.js
+++ b/lib/core/config.js
@@ -26,6 +26,7 @@ var folder = process.platform === 'win32'
 var config = require('rc') ('bower', {
   cache      :  path.join(roaming, folder, 'cache'),
   links      :  path.join(roaming, folder, 'links'),
+  completion :  path.join(roaming, folder, 'completion'),
   json       : 'component.json',
   endpoint   : 'https://bower.herokuapp.com',
   directory  : 'components'
@@ -41,4 +42,4 @@ if (fileExists(localFile)) {
 // If an uncaught exception occurs, the temporary directories will be deleted nevertheless
 tmp.setGracefulCleanup();
 
-module.exports = config;
\ No newline at end of file
+module.exports = config;
diff --git a/lib/util/completion.js b/lib/util/completion.js
new file mode 100644
index 00000000..3d222f09
--- /dev/null
+++ b/lib/util/completion.js
@@ -0,0 +1,65 @@
+// ==========================================
+// BOWER: completion
+// ==========================================
+// Copyright 2012 Twitter, Inc
+// Licensed under The MIT License
+// http://opensource.org/licenses/MIT
+// ==========================================
+
+// This module exposes a simple helper to parse the environment variables in
+// case of a tab completion command. It parses the provided `argv` (nopt's
+// remain arguments after `--`) and `env` (should be process.env)
+//
+// It is inspired and based off Isaac's work on npm.
+
+module.exports = function (argv, env) {
+  var opts = {};
+
+  // w is the words number, based on the cursor position
+  opts.w = +env.COMP_CWORD;
+
+  // words is the escaped sequence of words following `bower`
+  opts.words = argv.map(function (word) {
+    return word.charAt(0) === "\"" ?
+      word.replace(/^"|"$/g, "") :
+      word.replace(/\\ /g, " ");
+  });
+
+  // word is a shortcut to the last word in the line
+  opts.word = opts.words[opts.w - 1];
+
+  // line is the sequence of tab completed words.
+  opts.line = env.COMP_LINE;
+
+  // point is the cursor position in the line
+  opts.point = +env.COMP_POINT;
+
+  // length is the whole line's length.
+  opts.length = opts.line.length;
+
+  // partialLine is the line ignoring the sequence of characters after
+  // cursor position, ie. tabbing at: bower install j|qu
+  // gives back a partialLine: bower install j
+  opts.partialLine = opts.line.slice(0, opts.point);
+
+  // partialWords is only returning the words based on cursor position,
+  // ie tabbing at: bower install ze|pto backbone
+  // gives back a partialWords array: ['install', 'zepto']
+  opts.partialWords = opts.words.slice(0, opts.w);
+
+  return opts;
+};
+
+module.exports.log = function (arr, opts, prefix) {
+  arr = Array.isArray(arr) ? arr : [arr];
+  arr.filter(module.exports.abbrev(opts)).forEach(function (word) {
+    console.log(word);
+  });
+};
+
+module.exports.abbrev = function abbrev(opts) {
+  var word = opts.word.replace(/\./g, '\\.');
+  return function (it) {
+    return new RegExp('^' + word).test(it);
+  };
+};
diff --git a/templates/completion.mustache b/templates/completion.mustache
new file mode 100644
index 00000000..90e3a65c
--- /dev/null
+++ b/templates/completion.mustache
@@ -0,0 +1,55 @@
+# Credits to npm's. Awesome completion utility.
+#
+# Bower completion script, based on npm completion script.
+
+###-begin-bower-completion-###
+#
+# Installation: bower completion >> ~/.bashrc  (or ~/.zshrc)
+# Or, maybe: bower completion > /usr/local/etc/bash_completion.d/npm
+#
+
+COMP_WORDBREAKS=${COMP_WORDBREAKS/=/}
+COMP_WORDBREAKS=${COMP_WORDBREAKS/@/}
+export COMP_WORDBREAKS
+
+if type complete &>/dev/null; then
+  _bower_completion () {
+    local si="$IFS"
+    IFS=$'\n' COMPREPLY=($(COMP_CWORD="$COMP_CWORD" \
+                           COMP_LINE="$COMP_LINE" \
+                           COMP_POINT="$COMP_POINT" \
+                           bower completion -- "${COMP_WORDS[@]}" \
+                           2>/dev/null)) || return $?
+    IFS="$si"
+  }
+  complete -F _bower_completion bower
+elif type compdef &>/dev/null; then
+  _bower_completion() {
+    si=$IFS
+    compadd -- $(COMP_CWORD=$((CURRENT-1)) \
+                 COMP_LINE=$BUFFER \
+                 COMP_POINT=0 \
+                 bower completion -- "${words[@]}" \
+                 2>/dev/null)
+    IFS=$si
+  }
+  compdef _bower_completion bower
+elif type compctl &>/dev/null; then
+  _bower_completion () {
+    local cword line point words si
+    read -Ac words
+    read -cn cword
+    let cword-=1
+    read -l line
+    read -ln point
+    si="$IFS"
+    IFS=$'\n' reply=($(COMP_CWORD="$cword" \
+                       COMP_LINE="$line" \
+                       COMP_POINT="$point" \
+                       bower completion -- "${words[@]}" \
+                       2>/dev/null)) || return $?
+    IFS="$si"
+  }
+  compctl -K _bower_completion bower
+fi
+###-end-bower-completion-###
diff --git a/templates/help-completion.mustache b/templates/help-completion.mustache
new file mode 100644
index 00000000..32e058d4
--- /dev/null
+++ b/templates/help-completion.mustache
@@ -0,0 +1,12 @@
+
+Usage:
+
+    {{#cyan}}bower{{/cyan}} completion
+
+Synopsis:
+
+    . <(bower completion)
+
+Description:
+
+    Tab Completion for bower
diff --git a/test/completion.js b/test/completion.js
new file mode 100644
index 00000000..cbe6af74
--- /dev/null
+++ b/test/completion.js
@@ -0,0 +1,129 @@
+/*jshint plusplus:false*/
+
+var fs     = require('fs');
+var path   = require('path');
+var assert = require('assert');
+
+var complete = require('../lib/util/completion');
+var command  = require('../lib/commands/completion');
+var commands = require('../lib/commands');
+
+describe('completion', function () {
+
+  before(function () {
+    this.opts = complete(['bower', 'install'], {
+      COMP_CWORD: '2',
+      COMP_LINE: 'bower install',
+      COMP_POINT: '14'
+    });
+  });
+
+  beforeEach(function() {
+    this.log = complete.log;
+  });
+
+  afterEach(function () {
+    complete.log = this.log;
+  });
+
+  it('parses COMP_* in the env', function () {
+    assert.deepEqual(this.opts, {
+      w:            2,
+      words:        [ 'bower', 'install' ],
+      word:         'install',
+      line:         'bower install',
+      point:        14,
+      length:       13,
+      partialLine:  'bower install',
+      partialWords: [ 'bower', 'install' ]
+    });
+  });
+
+
+  it('filters out completion results', function () {
+    var completed = [
+      'backbone',
+      'backbone-forms',
+      'backbone-paginator',
+      'backbone.forms',
+      'backbone.paginator'
+    ];
+
+    var all = complete.abbrev({ word: 'ba' });
+    var none = complete.abbrev({ word: 'foobar' });
+    var form = complete.abbrev({ word: 'backbone-form' });
+    var dots = complete.abbrev({ word: 'backbone.' });
+    var dashed = complete.abbrev({ word: 'backbone-' });
+
+    assert.deepEqual(completed.filter(all), completed);
+    assert.deepEqual(completed.filter(none), []);
+    assert.deepEqual(completed.filter(form), ['backbone-forms']);
+    assert.deepEqual(completed.filter(dashed), ['backbone-forms', 'backbone-paginator']);
+    assert.deepEqual(completed.filter(dots), ['backbone.forms', 'backbone.paginator']);
+  });
+
+
+  it('dumps the script when COMP_* aren\'t in the env', function (done) {
+    command().on('end', function (data) {
+      var script = fs.readFileSync(path.join(__dirname, '../templates/completion.mustache'), 'utf8');
+      assert.equal(data, script);
+      done();
+    });
+  });
+
+  it('completes the list of command on first word', function () {
+    complete.log = function (results, opts) {
+      assert.deepEqual(results, Object.keys(commands));
+    };
+
+    command([''], {
+      COMP_CWORD: '1',
+      COMP_LINE: 'bower ',
+      COMP_POINT: '6'
+    });
+  });
+
+  it('completes the list of options on first word', function () {
+    complete.log = function (results, opts) {
+      assert.deepEqual(results, ['--no-color', '--help', '--version']);
+    };
+
+    command(['-'], {
+      COMP_CWORD: '1',
+      COMP_LINE: 'bower -',
+      COMP_POINT: '7'
+    });
+  });
+
+  it('completes the list of command on invalid command', function () {
+    complete.log = function (results, opts) {
+      assert.deepEqual(results, Object.keys(commands));
+    };
+
+    command(['foobar'], {
+      COMP_CWORD: '1',
+      COMP_LINE: 'bower foobar',
+      COMP_POINT: '12'
+    });
+  });
+
+  it('delegates to command.completion for each bower command', function (done) {
+    complete.log = function (results, opts) {
+      assert.ok(results.length);
+
+      var jq = results.filter(function (res) {
+        return res === 'jquery';
+      });
+
+      assert.equal(jq.length, 1);
+    };
+
+    var cmd = command(['install', 'jquery-'], {
+      COMP_CWORD: '2',
+      COMP_LINE: 'bower install jquery-',
+      COMP_POINT: '14'
+    });
+
+    cmd.on('end', done);
+  });
+});