diff --git a/lib/with_model/minitest.rb b/lib/with_model/minitest.rb
new file mode 100644
index 0000000..6fc24ec
--- /dev/null
+++ b/lib/with_model/minitest.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require "minitest"
+require "with_model"
+
+WithModel.runner = :minitest
+Minitest::Test.extend WithModel
diff --git a/lib/with_model/rspec.rb b/lib/with_model/rspec.rb
new file mode 100644
index 0000000..1a8a98c
--- /dev/null
+++ b/lib/with_model/rspec.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require "rspec/core"
+require "with_model"
+
+WithModel.runner = :rspec
+
+RSpec.configure do |config|
+  config.extend WithModel
+end
diff --git a/lib/with_model/test_unit.rb b/lib/with_model/test_unit.rb
new file mode 100644
index 0000000..d8781a2
--- /dev/null
+++ b/lib/with_model/test_unit.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require "test/unit"
+require "with_model"
+
+WithModel.runner = :test_unit
+Test::Unit::TestCase.extend WithModel
diff --git a/spec/runner_entrypoints_spec.rb b/spec/runner_entrypoints_spec.rb
new file mode 100644
index 0000000..e181a2c
--- /dev/null
+++ b/spec/runner_entrypoints_spec.rb
@@ -0,0 +1,153 @@
+# frozen_string_literal: true
+
+require "open3"
+require "rbconfig"
+require "tmpdir"
+
+RSpec.describe "runner integration entrypoints" do
+  def run_ruby(source, load_paths: ["lib"])
+    Open3.capture3(
+      RbConfig.ruby,
+      *load_paths.map { |path| "-I#{path}" },
+      "-e",
+      source
+    )
+  end
+
+  def expect_native_runner_to_pass(source, load_paths: ["lib"])
+    stdout, stderr, status = run_ruby(source, load_paths:)
+
+    expect(status).to be_success, <<~MESSAGE
+      subprocess failed with status #{status.exitstatus}
+      stdout:
+      #{stdout}
+      stderr:
+      #{stderr}
+    MESSAGE
+  end
+
+  it "configures RSpec and extends new example groups" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "with_model/rspec"
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :rspec
+
+      RSpec.describe "entrypoint" do
+        it "installs the DSL" do
+          expect(self.class).to respond_to(:with_model)
+        end
+      end
+
+      exit RSpec::Core::Runner.run([])
+    RUBY
+  end
+
+  it "configures Minitest and extends new test subclasses" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "with_model/minitest"
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :minitest
+
+      # Assert that minitest/autorun is not loaded
+      autorun_loaded = $LOADED_FEATURES.any? { |f| f.end_with?("/minitest/autorun.rb") }
+      abort "autorun should not be loaded; loaded features: #{$LOADED_FEATURES.inspect}" if autorun_loaded
+
+      class MinitestEntrypointTest < Minitest::Test
+        def test_installs_the_dsl
+          assert_respond_to self.class, :with_model
+        end
+      end
+
+      exit(Minitest.run ? 0 : 1)
+    RUBY
+  end
+
+  it "configures Test::Unit and extends new test subclasses" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "with_model/test_unit"
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :test_unit
+
+      class TestUnitEntrypointTest < Test::Unit::TestCase
+        def test_installs_the_dsl
+          assert_respond_to self.class, :with_model
+        end
+      end
+    RUBY
+  end
+
+  it "propagates Test::Unit's LoadError when the framework is unavailable" do
+    Dir.mktmpdir do |directory|
+      Dir.mkdir(File.join(directory, "test"))
+      File.write(
+        File.join(directory, "test/unit.rb"),
+        'raise LoadError, "distinctive test/unit LoadError"'
+      )
+
+      expect_native_runner_to_pass(<<~'RUBY', load_paths: [directory, "lib"])
+        begin
+          require "with_model/test_unit"
+        rescue LoadError => error
+          abort "unexpected LoadError: #{error.message.inspect}" unless
+            error.message == "distinctive test/unit LoadError"
+        else
+          abort "expected a LoadError"
+        end
+      RUBY
+    end
+  end
+
+  it "retains manual Test::Unit setup with plain with_model" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "test/unit"
+      require "with_model"
+
+      WithModel.runner = :test_unit
+      Test::Unit::TestCase.extend WithModel
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :test_unit
+
+      class PlainWithModelTestUnitTest < Test::Unit::TestCase
+        def test_installs_the_dsl
+          assert_respond_to self.class, :with_model
+        end
+      end
+    RUBY
+  end
+
+  it "retains manual RSpec setup with plain with_model" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "rspec"
+      require "with_model"
+
+      WithModel.runner = :rspec
+      RSpec.configure do |config|
+        config.extend WithModel
+      end
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :rspec
+
+      RSpec.describe "entrypoint" do
+        it "installs the DSL" do
+          expect(self.class).to respond_to(:with_model)
+        end
+      end
+
+      exit RSpec::Core::Runner.run([])
+    RUBY
+  end
+
+  it "retains manual Minitest setup with plain with_model" do
+    expect_native_runner_to_pass(<<~'RUBY')
+      require "minitest"
+      require "with_model"
+
+      WithModel.runner = :minitest
+      Minitest::Test.extend WithModel
+      abort "runner: #{WithModel.runner.inspect}" unless WithModel.runner == :minitest
+
+      class PlainWithModelMinitestTest < Minitest::Test
+        def test_installs_the_dsl
+          assert_respond_to self.class, :with_model
+        end
+      end
+
+      exit(Minitest.run ? 0 : 1)
+    RUBY
+  end
+end