diff --git a/config/default.yml b/config/default.yml
index 9d95fd4e..fadcb1c7 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -784,6 +784,15 @@ PostCheckout:
       - 'Gemfile.lock'
       - '*.gemspec'
 
+  ComposerInstall:
+    enabled: false
+    description: 'Install composer dependencies'
+    requires_files: true
+    required_executable: 'composer'
+    install_command: 'curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer'
+    flags: ['install']
+    include: 'composer.json'
+
   IndexTags:
     enabled: false
     description: 'Generate tags file from source'
@@ -851,6 +860,15 @@ PostCommit:
     install_command: 'npm install --save-dev commitplease'
     flags: ['-1']
 
+  ComposerInstall:
+    enabled: false
+    description: 'Install composer dependencies'
+    requires_files: true
+    required_executable: 'composer'
+    install_command: 'curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer'
+    flags: ['install']
+    include: 'composer.json'
+
   GitGuilt:
     enabled: false
     description: 'Calculate changes in blame since last commit'
@@ -918,6 +936,15 @@ PostMerge:
       - 'Gemfile.lock'
       - '*.gemspec'
 
+  ComposerInstall:
+    enabled: false
+    description: 'Install composer dependencies'
+    requires_files: true
+    required_executable: 'composer'
+    install_command: 'curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer'
+    flags: ['install']
+    include: 'composer.json'
+
   IndexTags:
     enabled: false
     description: 'Generate tags file from source'
@@ -977,6 +1004,15 @@ PostRewrite:
       - 'Gemfile.lock'
       - '*.gemspec'
 
+  ComposerInstall:
+    enabled: false
+    description: 'Install composer dependencies'
+    requires_files: true
+    required_executable: 'composer'
+    install_command: 'curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer'
+    flags: ['install']
+    include: 'composer.json'
+
   IndexTags:
     enabled: false
     description: 'Generate tags file from source'
diff --git a/lib/overcommit/hook/post_checkout/composer_install.rb b/lib/overcommit/hook/post_checkout/composer_install.rb
new file mode 100644
index 00000000..28573343
--- /dev/null
+++ b/lib/overcommit/hook/post_checkout/composer_install.rb
@@ -0,0 +1,11 @@
+require 'overcommit/hook/shared/composer_install'
+
+module Overcommit::Hook::PostCheckout
+  # Runs `composer install` when a change is detected in the repository's
+  # dependencies.
+  #
+  # @see {Overcommit::Hook::Shared::ComposerInstall}
+  class ComposerInstall < Base
+    include Overcommit::Hook::Shared::ComposerInstall
+  end
+end
diff --git a/lib/overcommit/hook/post_commit/composer_install.rb b/lib/overcommit/hook/post_commit/composer_install.rb
new file mode 100644
index 00000000..218c8140
--- /dev/null
+++ b/lib/overcommit/hook/post_commit/composer_install.rb
@@ -0,0 +1,11 @@
+require 'overcommit/hook/shared/composer_install'
+
+module Overcommit::Hook::PostCommit
+  # Runs `composer install` when a change is detected in the repository's
+  # dependencies.
+  #
+  # @see {Overcommit::Hook::Shared::ComposerInstall}
+  class ComposerInstall < Base
+    include Overcommit::Hook::Shared::ComposerInstall
+  end
+end
diff --git a/lib/overcommit/hook/post_merge/composer_install.rb b/lib/overcommit/hook/post_merge/composer_install.rb
new file mode 100644
index 00000000..ec17a5a8
--- /dev/null
+++ b/lib/overcommit/hook/post_merge/composer_install.rb
@@ -0,0 +1,11 @@
+require 'overcommit/hook/shared/composer_install'
+
+module Overcommit::Hook::PostMerge
+  # Runs `composer install` when a change is detected in the repository's
+  # dependencies.
+  #
+  # @see {Overcommit::Hook::Shared::ComposerInstall}
+  class ComposerInstall < Base
+    include Overcommit::Hook::Shared::ComposerInstall
+  end
+end
diff --git a/lib/overcommit/hook/post_rewrite/composer_install.rb b/lib/overcommit/hook/post_rewrite/composer_install.rb
new file mode 100644
index 00000000..354d6e50
--- /dev/null
+++ b/lib/overcommit/hook/post_rewrite/composer_install.rb
@@ -0,0 +1,11 @@
+require 'overcommit/hook/shared/composer_install'
+
+module Overcommit::Hook::PostRewrite
+  # Runs `composer install` when a change is detected in the repository's
+  # dependencies.
+  #
+  # @see {Overcommit::Hook::Shared::ComposerInstall}
+  class ComposerInstall < Base
+    include Overcommit::Hook::Shared::ComposerInstall
+  end
+end
diff --git a/lib/overcommit/hook/shared/composer_install.rb b/lib/overcommit/hook/shared/composer_install.rb
new file mode 100644
index 00000000..828484e6
--- /dev/null
+++ b/lib/overcommit/hook/shared/composer_install.rb
@@ -0,0 +1,13 @@
+module Overcommit::Hook::Shared
+  # Shared code used by all ComposerInstall hooks. Runs `composer install` when
+  # a change is detected in the repository's dependencies.
+  #
+  # @see https://getcomposer.org/
+  module ComposerInstall
+    def run
+      result = execute(command)
+      return :fail, result.stdout unless result.success?
+      :pass
+    end
+  end
+end
diff --git a/spec/overcommit/hook/post_checkout/composer_install_spec.rb b/spec/overcommit/hook/post_checkout/composer_install_spec.rb
new file mode 100644
index 00000000..bf041e6f
--- /dev/null
+++ b/spec/overcommit/hook/post_checkout/composer_install_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PostCheckout::ComposerInstall do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when composer install exits successfully' do
+    before do
+      result.stub(:success?).and_return(true)
+    end
+
+    it { should pass }
+  end
+
+  context 'when composer install exits unsuccessfully' do
+    before do
+      result.stub(success?: false, stdout: 'Composer could not find a composer.json file')
+    end
+
+    it { should fail_hook }
+  end
+end
diff --git a/spec/overcommit/hook/post_commit/composer_install_spec.rb b/spec/overcommit/hook/post_commit/composer_install_spec.rb
new file mode 100644
index 00000000..499ec8ea
--- /dev/null
+++ b/spec/overcommit/hook/post_commit/composer_install_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PostCommit::ComposerInstall do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when composer install exits successfully' do
+    before do
+      result.stub(:success?).and_return(true)
+    end
+
+    it { should pass }
+  end
+
+  context 'when composer install exits unsuccessfully' do
+    before do
+      result.stub(success?: false, stdout: 'Composer could not find a composer.json file')
+    end
+
+    it { should fail_hook }
+  end
+end
diff --git a/spec/overcommit/hook/post_merge/composer_install_spec.rb b/spec/overcommit/hook/post_merge/composer_install_spec.rb
new file mode 100644
index 00000000..fb092bc2
--- /dev/null
+++ b/spec/overcommit/hook/post_merge/composer_install_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PostMerge::ComposerInstall do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when composer install exits successfully' do
+    before do
+      result.stub(:success?).and_return(true)
+    end
+
+    it { should pass }
+  end
+
+  context 'when composer install exits unsuccessfully' do
+    before do
+      result.stub(success?: false, stdout: 'Composer could not find a composer.json file')
+    end
+
+    it { should fail_hook }
+  end
+end
diff --git a/spec/overcommit/hook/post_rewrite/composer_install_spec.rb b/spec/overcommit/hook/post_rewrite/composer_install_spec.rb
new file mode 100644
index 00000000..fd44d43c
--- /dev/null
+++ b/spec/overcommit/hook/post_rewrite/composer_install_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PostRewrite::ComposerInstall do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when composer install exits successfully' do
+    before do
+      result.stub(:success?).and_return(true)
+    end
+
+    it { should pass }
+  end
+
+  context 'when composer install exits unsuccessfully' do
+    before do
+      result.stub(success?: false, stdout: 'Composer could not find a composer.json file')
+    end
+
+    it { should fail_hook }
+  end
+end