diff --git a/.mutant.yml b/.mutant.yml
index bc0d94b..ce348a0 100644
--- a/.mutant.yml
+++ b/.mutant.yml
@@ -3,6 +3,8 @@ includes:
 - lib
 - test
 requires:
+- sequel
+- active_record
 - en57
 integration:
   name: minitest
diff --git a/lib/en57.rb b/lib/en57.rb
index 4113a62..4c90f18 100644
--- a/lib/en57.rb
+++ b/lib/en57.rb
@@ -6,8 +6,8 @@ require_relative "en57/json_serializer"
 require_relative "en57/query"
 require_relative "en57/scope"
 require_relative "en57/pg_adapter"
-require_relative "en57/sequel_adapter"
-require_relative "en57/active_record_adapter"
+require_relative "en57/sequel_adapter" if defined?(Sequel)
+require_relative "en57/active_record_adapter" if defined?(ActiveRecord)
 require_relative "en57/repository"
 require_relative "en57/event_store"
 
diff --git a/test/test_en57.rb b/test/test_en57.rb
index d1faa9d..b8c2900 100644
--- a/test/test_en57.rb
+++ b/test/test_en57.rb
@@ -9,5 +9,41 @@ module En57
     def test_that_it_has_a_version_number
       refute_nil VERSION
     end
+
+    def test_requiring_en57_without_sequel_skips_sequel_adapter
+      assert_ruby(<<~RUBY)
+        require "en57"
+        abort "loaded SequelAdapter" if defined?(En57::SequelAdapter)
+      RUBY
+    end
+
+    def test_requiring_en57_without_active_record_skips_active_record_adapter
+      assert_ruby(<<~RUBY)
+        require "en57"
+        abort "loaded ActiveRecordAdapter" if defined?(En57::ActiveRecordAdapter)
+      RUBY
+    end
+
+    private
+
+    def assert_ruby(script)
+      reader, writer = IO.pipe
+      pid =
+        Process.spawn(
+          RbConfig.ruby,
+          "-Ilib",
+          "-e",
+          script,
+          out: writer,
+          err: writer,
+        )
+      writer.close
+      output = reader.read
+      _, status = Process.wait2(pid)
+
+      assert status.success?, output
+    ensure
+      reader&.close
+    end
   end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 5893b6a..2aab2ee 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -4,12 +4,12 @@ require "minitest/autorun"
 require "minitest/mock"
 require "mutant/minitest/coverage"
 
+require "sequel"
+require "active_record"
 require "en57"
 require "securerandom"
 require "concurrent-ruby"
 require "pg_ephemeral"
-require "sequel"
-require "active_record"
 
 module En57
   class IntegrationTest < Minitest::Test