diff --git a/plugins/provisioners/salt/provisioner.rb b/plugins/provisioners/salt/provisioner.rb
index 62c167b3c..bf462df12 100644
--- a/plugins/provisioners/salt/provisioner.rb
+++ b/plugins/provisioners/salt/provisioner.rb
@@ -143,6 +143,13 @@ module VagrantPlugins
           options = "%s %s" % [options, @config.install_args]
         end
 
+        if @config.install_command
+          # If this is defined, we will ignore both install_type and
+          # install_args and use this instead. Every necessary command option
+          # will need to be specified by the user.
+          options = @config.install_command
+        end
+
         if @config.verbose
           @machine.env.ui.info "Using Bootstrap Options: %s" % options
         end
diff --git a/website/docs/source/v2/provisioning/salt.html.md b/website/docs/source/v2/provisioning/salt.html.md
index a34bc4d43..7dbd9777f 100644
--- a/website/docs/source/v2/provisioning/salt.html.md
+++ b/website/docs/source/v2/provisioning/salt.html.md
@@ -60,7 +60,13 @@ distribution's stable package manager, git tree-ish, daily ppa, or testing repos
 Not supported on Windows.
 
 * `install_args` (develop) - When performing a git install,
-you can specify a branch, tag, or any treeish. Not supported on Windows.
+you can specify a branch, tag, or any treeish. If using the `custom` install type,
+you can also specify a different repository to install from.
+Not supported on Windows.
+
+* `install_command` (string) - Allow specifying an arbitrary string of arguments
+to the bootstrap script. This will completely ignore `install_type` and `install_args`
+to allow more flexibility with the bootstrap process.
 
 * `always_install`   (boolean) - Installs salt binaries even
  if they are already detected, default `false`