diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa97eaf..745e74d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 - Added `avg`, `cardinality`, `max`, `min`, and `sum` aggregations
 - Added `load: {dumpable: true}` option
+- Added `index_suffix` option
 - Accept string for `exclude` option
 
 ## 2.2.0
diff --git a/README.md b/README.md
index ba90c4d..b006c15 100644
--- a/README.md
+++ b/README.md
@@ -1770,6 +1770,14 @@ product = FactoryGirl.create(:product)
 product.reindex(refresh: true)
 ```
 
+### Parallel Tests
+
+Set:
+
+```ruby
+Searchkick.index_suffix = ENV["TEST_ENV_NUMBER"]
+```
+
 ## Multi-Tenancy
 
 Check out [this great post](https://www.tiagoamaro.com.br/2014/12/11/multi-tenancy-with-searchkick/) on the [Apartment](https://github.com/influitive/apartment) gem. Follow a similar pattern if you use another gem.
diff --git a/Rakefile b/Rakefile
index 93c1699..8c215e6 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,6 +1,13 @@
 require "bundler/gem_tasks"
 require "rake/testtask"
 
+begin
+  require "parallel_tests/tasks"
+  require "shellwords"
+rescue LoadError
+  # do nothing
+end
+
 task default: :test
 Rake::TestTask.new do |t|
   t.libs << "test"
diff --git a/lib/searchkick.rb b/lib/searchkick.rb
index b73703a..391cab3 100644
--- a/lib/searchkick.rb
+++ b/lib/searchkick.rb
@@ -36,7 +36,7 @@ module Searchkick
   class ImportError < Error; end
 
   class << self
-    attr_accessor :search_method_name, :wordnet_path, :timeout, :models, :client_options, :redis
+    attr_accessor :search_method_name, :wordnet_path, :timeout, :models, :client_options, :redis, :index_suffix
     attr_writer :client, :env, :search_timeout
     attr_reader :aws_credentials
   end
diff --git a/lib/searchkick/model.rb b/lib/searchkick/model.rb
index bc936af..ebe5b74 100644
--- a/lib/searchkick/model.rb
+++ b/lib/searchkick/model.rb
@@ -21,8 +21,8 @@ module Searchkick
         class_variable_set :@@searchkick_klass, self
         class_variable_set :@@searchkick_callbacks, callbacks
         class_variable_set :@@searchkick_index, options[:index_name] ||
-          (options[:index_prefix].respond_to?(:call) && proc { [options[:index_prefix].call, model_name.plural, Searchkick.env].compact.join("_") }) ||
-          [options[:index_prefix], model_name.plural, Searchkick.env].compact.join("_")
+          (options[:index_prefix].respond_to?(:call) && proc { [options[:index_prefix].call, model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_") }) ||
+          [options[:index_prefix], model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_")
 
         class << self
           def searchkick_search(term = "*", **options, &block)
diff --git a/test/gemfiles/parallel_tests.gemfile b/test/gemfiles/parallel_tests.gemfile
new file mode 100644
index 0000000..73ba4b0
--- /dev/null
+++ b/test/gemfiles/parallel_tests.gemfile
@@ -0,0 +1,8 @@
+source 'https://rubygems.org'
+
+# Specify your gem's dependencies in searchkick.gemspec
+gemspec path: "../../"
+
+gem "sqlite3"
+gem "activerecord", "~> 5.0.0"
+gem "parallel_tests"
diff --git a/test/index_test.rb b/test/index_test.rb
index 13e01eb..f1397a9 100644
--- a/test/index_test.rb
+++ b/test/index_test.rb
@@ -7,8 +7,9 @@ class IndexTest < Minitest::Test
   end
 
   def test_clean_indices
-    old_index = Searchkick::Index.new("products_test_20130801000000000")
-    different_index = Searchkick::Index.new("items_test_20130801000000000")
+    suffix = Searchkick.index_suffix ? "_#{Searchkick.index_suffix}" : ""
+    old_index = Searchkick::Index.new("products_test#{suffix}_20130801000000000")
+    different_index = Searchkick::Index.new("items_test#{suffix}_20130801000000000")
 
     old_index.delete if old_index.exists?
     different_index.delete if different_index.exists?
@@ -25,7 +26,8 @@ class IndexTest < Minitest::Test
   end
 
   def test_clean_indices_old_format
-    old_index = Searchkick::Index.new("products_test_20130801000000")
+    suffix = Searchkick.index_suffix ? "_#{Searchkick.index_suffix}" : ""
+    old_index = Searchkick::Index.new("products_test#{suffix}_20130801000000")
     old_index.create
 
     Product.searchkick_index.clean_indices
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 82e378e..c151d6b 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -6,11 +6,16 @@ require "logger"
 require "active_support/core_ext" if defined?(NoBrainer)
 require "active_support/notifications"
 
+Searchkick.index_suffix = ENV["TEST_ENV_NUMBER"]
+
 ENV["RACK_ENV"] = "test"
 
 Minitest::Test = Minitest::Unit::TestCase unless defined?(Minitest::Test)
 
-File.delete("elasticsearch.log") if File.exist?("elasticsearch.log")
+if !defined?(ParallelTests) || ParallelTests.first_process?
+  File.delete("elasticsearch.log") if File.exist?("elasticsearch.log")
+end
+
 Searchkick.client.transport.logger = Logger.new("elasticsearch.log")
 Searchkick.search_timeout = 5
 
@@ -466,7 +471,7 @@ class Animal
   searchkick \
     text_start: [:name],
     suggest: [:name],
-    index_name: -> { "#{name.tableize}-#{Date.today.year}" },
+    index_name: -> { "#{name.tableize}-#{Date.today.year}#{Searchkick.index_suffix}" },
     callbacks: defined?(ActiveJob) ? :async : true
     # wordnet: true
 end
--
libgit2 0.21.0