diff --git a/README.md b/README.md
index 734b423e..3bfae925 100644
--- a/README.md
+++ b/README.md
@@ -186,6 +186,14 @@ You can get further information on how to use U3d by running `u3d --help` (or `u
 
 ## How-tos
 
+### Install in a custom location
+
+`u3d install` accepts an argument `--installation_path` which can install unity and its additional components to the location you want.
+
+However, there is a pitfall to that: you need to tell u3d where to look for the versions you installed in custom location. Doing so is quite easy, you just have to set the `U3D_EXTRA_PATHS`, to a list of paths that you want u3d to look for versions.
+
+_NOTE:_ The list of paths `U3D_EXTRA_PATHS` is formatted as your standard `PATH`, ie `U3D_EXTRA_PATHS=/path/to/something:/another/path` on Unix systems, and `U3D_EXTRA_PATHS=C:\Path\To\Something;E:\Another\Path` on Windows.
+
 ### Run several Unity instances in parallel
 
 The only thing you have to watch for while trying to run multiple instances of Unity in parallel is the fact that they will share the same log file by default (the `Editor.log`). Therefore you will have to specify it using the [command line arguments](https://docs.unity3d.com/Manual/CommandLineArguments.html), you can do so with u3d the following way from each of your project root folder:
diff --git a/lib/u3d/installer.rb b/lib/u3d/installer.rb
index b9df3707..142a535d 100644
--- a/lib/u3d/installer.rb
+++ b/lib/u3d/installer.rb
@@ -86,6 +86,21 @@ def installed_sorted_by_versions
       return [] if list.empty?
       list.sort { |a, b| UnityVersionComparator.new(a.version) <=> UnityVersionComparator.new(b.version) }
     end
+
+    protected
+
+    def extra_installation_paths
+      return [] if ENV['U3D_EXTRA_PATHS'].nil?
+      ENV['U3D_EXTRA_PATHS'].strip.split(File::PATH_SEPARATOR)
+    end
+
+    def find_installations_with_path(default_root_path: '', postfix: [])
+      ([default_root_path] | extra_installation_paths).map do |path|
+        UI.verbose "Looking for installed Unity version under #{path}"
+        pattern = File.join([path] + postfix)
+        Dir.glob(pattern).map { |found_path| yield found_path }
+      end.flatten
+    end
   end
 
   # deprecated
@@ -169,9 +184,14 @@ def uninstall(unity: nil)
     private
 
     def list_installed_paths
-      find = File.join(DEFAULT_MAC_INSTALL, 'Applications', 'Unity*', 'Unity.app')
-      paths = Dir[find]
-      paths = paths.map { |u| Pathname.new(u).parent.to_s }
+      paths = find_installations_with_path(
+        default_root_path: DEFAULT_MAC_INSTALL,
+        postfix: %w[
+          Applications
+          Unity*
+          Unity.app
+        ]
+      ) { |u| Pathname.new(u).parent.to_s }
       UI.verbose "Found list_installed_paths: #{paths}"
       paths
     end
@@ -332,17 +352,25 @@ def pkg_install_path(unity_root_path, pinfo_path)
     end
 
     def list_installed_paths
-      find = File.join(DEFAULT_LINUX_INSTALL, 'unity-editor-*', 'Editor')
-      paths = Dir[find]
-      paths = paths.map { |u| Pathname.new(u).parent.to_s }
+      paths = find_installations_with_path(
+        default_root_path: DEFAULT_LINUX_INSTALL,
+        postfix: %w[
+          unity-editor-*
+          Editor
+        ]
+      ) { |u| Pathname.new(u).parent.to_s }
       UI.verbose "Found list_installed_paths: #{paths}"
       paths
     end
 
     def debian_installed_paths
-      find = File.join(DEFAULT_LINUX_INSTALL, 'Unity', 'Editor')
-      paths = Dir[find]
-      paths = paths.map { |u| Pathname.new(u).parent.to_s }
+      paths = find_installations_with_path(
+        default_root_path: DEFAULT_LINUX_INSTALL,
+        postfix: %w[
+          Unity
+          Editor
+        ]
+      ) { |u| Pathname.new(u).parent.to_s }
       UI.verbose "Found debian_installed_paths: #{paths}"
       paths
     end
@@ -362,8 +390,14 @@ def sanitize_install(unity, long: false, dry_run: false)
     end
 
     def installed
-      find = File.join(DEFAULT_WINDOWS_INSTALL, 'Unity*', 'Editor', 'Uninstall.exe')
-      Dir[find].map { |path| WindowsInstallation.new(root_path: File.expand_path('../..', path)) }
+      find_installations_with_path(
+        default_root_path: DEFAULT_WINDOWS_INSTALL,
+        postfix: %w[
+          Unity*
+          Editor
+          Uninstall.exe
+        ]
+      ) { |path| WindowsInstallation.new(root_path: File.expand_path('../..', path)) }
     end
 
     def install(file_path, version, installation_path: nil, info: {})
diff --git a/spec/support/installations.rb b/spec/support/installations.rb
index 1ac3d451..343b2544 100644
--- a/spec/support/installations.rb
+++ b/spec/support/installations.rb
@@ -31,6 +31,16 @@ def macinstall_5_6_default
   return unity
 end
 
+def macinstall_5_6_custom_location
+  unity = double("MacInstallation")
+  # allow(unity).to receive(:path) { '/Applications/Unity/Unity.app' }
+  allow(unity).to receive(:version) { '5.6.0f1' }
+  allow(unity).to receive(:build_number) { 'bf5cca3e2788' }
+  allow(unity).to receive(:clean_install?) { false }
+  allow(unity).to receive(:root_path) { '/tmp/Applications/Unity' }
+  return unity
+end
+
 def macinstall_5_6_custom_with_space
   unity = double("MacInstallation")
   # allow(unity).to receive(:path) { '/Applications/Unity 5.6.0f1/Unity.app' }
@@ -89,6 +99,15 @@ def windows_2017_1_64bits_renamed
   return unity
 end
 
+def windows_2017_1_64bits_custom_location
+  unity = double("WindowsInstallation")
+  # allow(unity).to receive(:path) { 'C:/Program Files/Unity_2017.1.0f3' }
+  allow(unity).to receive(:version) { '2017.1.0f3' }
+  allow(unity).to receive(:build_number) { '472613c02cf7' }
+  allow(unity).to receive(:root_path) { 'E:/Program Files/Unity_2017.1.0f3' }
+  return unity
+end
+
 def fake_linux(version)
   unity = double("LinuxInstallation")
   allow(unity).to receive(:version) { version }
diff --git a/spec/u3d/installer_spec.rb b/spec/u3d/installer_spec.rb
index 0c5ce645..f8e74cfe 100644
--- a/spec/u3d/installer_spec.rb
+++ b/spec/u3d/installer_spec.rb
@@ -91,6 +91,59 @@ class DummyInstaller < U3d::BaseInstaller
     end
 
     describe U3d::MacInstaller, unless: WINDOWS do
+      describe '.list' do
+        it 'finds installs in default locations' do
+          unity = macinstall_5_6_default
+          installer = U3d::MacInstaller.new
+
+          allow(Dir).to receive(:glob).with('/Applications/Unity*/Unity.app') { ["#{unity.root_path}/Unity.app"] }
+          allow(U3d::MacInstallation).to receive(:new).with(root_path: unity.root_path) { unity }
+          allow(installer).to receive(:spotlight_installed_paths) { [] }
+
+          expect(installer.installed).to eql [unity]
+        end
+
+        it 'does not find installs in custom locations without U3D_EXTRA_PATHS' do
+          unity = macinstall_5_6_custom_location
+          installer = U3d::MacInstaller.new
+
+          allow(Dir).to receive(:glob).with('/Applications/Unity*/Unity.app') { [] }
+          allow(Dir).to receive(:glob).with('/tmp/Applications/Unity*/Unity.app') { ["#{unity.root_path}/Unity.app"] }
+          allow(U3d::MacInstallation).to receive(:new).with(root_path: unity.root_path) { unity }
+          allow(installer).to receive(:spotlight_installed_paths) { [] }
+
+          expect(installer.installed).to eql []
+        end
+
+        it 'finds installs in custom locations with U3D_EXTRA_PATHS' do
+          unity = macinstall_5_6_custom_location
+          installer = U3d::MacInstaller.new
+
+          allow(ENV).to receive(:[]).with('U3D_EXTRA_PATHS') { '/tmp' }
+          allow(Dir).to receive(:glob).with('/Applications/Unity*/Unity.app') { [] }
+          allow(Dir).to receive(:glob).with('/tmp/Applications/Unity*/Unity.app') { ["#{unity.root_path}/Unity.app"] }
+          allow(U3d::MacInstallation).to receive(:new).with(root_path: unity.root_path) { unity }
+          allow(installer).to receive(:spotlight_installed_paths) { [] }
+
+          expect(installer.installed).to eql [unity]
+        end
+
+        it 'finds both custom and default installs' do
+          unity_default = macinstall_5_6_default
+          unity_custom = macinstall_5_6_custom_location
+          installer = U3d::MacInstaller.new
+
+          allow(ENV).to receive(:[]).with('U3D_EXTRA_PATHS') { '/tmp' }
+          allow(Dir).to receive(:glob).with('/Applications/Unity*/Unity.app') { ["#{unity_default.root_path}/Unity.app"] }
+          allow(Dir).to receive(:glob).with('/tmp/Applications/Unity*/Unity.app') { ["#{unity_custom.root_path}/Unity.app"] }
+          allow(U3d::MacInstallation).to receive(:new).with(root_path: unity_default.root_path) { unity_default }
+          allow(U3d::MacInstallation).to receive(:new).with(root_path: unity_custom.root_path) { unity_custom }
+          allow(installer).to receive(:spotlight_installed_paths) { [] }
+
+          expect(installer.installed).to eql [unity_default, unity_custom]
+        end
+      end
+
       context 'when using a default install' do
         let(:unity) { macinstall_5_6_default }
         it 'sanitizes install' do
@@ -180,8 +233,8 @@ class DummyInstaller < U3d::BaseInstaller
           u1 = linux_5_6_standard
           u2 = linux_5_6_debian
           u3 = linux_2017_1_weird
-          allow(Dir).to receive(:[]).with('/opt/unity-editor-*/Editor') { ["#{u1.root_path}/Editor", "#{u3.root_path}/Editor"] }
-          allow(Dir).to receive(:[]).with('/opt/Unity/Editor') { ["#{u2.root_path}/Editor"] }
+          allow(Dir).to receive(:glob).with('/opt/unity-editor-*/Editor') { ["#{u1.root_path}/Editor", "#{u3.root_path}/Editor"] }
+          allow(Dir).to receive(:glob).with('/opt/Unity/Editor') { ["#{u2.root_path}/Editor"] }
 
           allow(U3d::LinuxInstallation).to receive(:new).with(root_path: u1.root_path) { u1 }
           allow(U3d::LinuxInstallation).to receive(:new).with(root_path: u2.root_path) { u2 }