diff --git a/CHANGELOG.md b/CHANGELOG.md
index c04cbec5..0b32d2b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 ### Added
 
 ### Fixed
+- The `--allow-attributes` flag now runs duplicate tests in different groups
 
 ## 4.6.0 - 2024-03-25
 
diff --git a/lib/parallel_tests/cli.rb b/lib/parallel_tests/cli.rb
index 003c41ed..d187b2f0 100644
--- a/lib/parallel_tests/cli.rb
+++ b/lib/parallel_tests/cli.rb
@@ -57,8 +57,8 @@ def execute_in_parallel(items, num_processes, options)
       Tempfile.open 'parallel_tests-lock' do |lock|
         ParallelTests.with_pid_file do
           simulate_output_for_ci options[:serialize_stdout] do
-            Parallel.map(items, in_threads: num_processes) do |item|
-              result = yield(item)
+            Parallel.map_with_index(items, in_threads: num_processes) do |item, index|
+              result = yield(item, index)
               reprint_output(result, lock.path) if options[:serialize_stdout]
               ParallelTests.stop_all_processes if options[:fail_fast] && result[:exit_status] != 0
               result
@@ -81,8 +81,8 @@ def run_tests_in_parallel(num_processes, options)
         end
 
         report_number_of_tests(groups) unless options[:quiet]
-        test_results = execute_in_parallel(groups, groups.size, options) do |group|
-          run_tests(group, groups.index(group), num_processes, options)
+        test_results = execute_in_parallel(groups, groups.size, options) do |group, index|
+          run_tests(group, index, num_processes, options)
         end
         report_results(test_results, options) unless options[:quiet]
       end
diff --git a/spec/parallel_tests/cli_spec.rb b/spec/parallel_tests/cli_spec.rb
index f5083996..d12c2e64 100644
--- a/spec/parallel_tests/cli_spec.rb
+++ b/spec/parallel_tests/cli_spec.rb
@@ -361,6 +361,45 @@ def self.it_prints_nothing_about_rerun_commands(options)
         subject.run(['test', '-n', '3', '--only-group', '2,3', '-t', 'my_test_runner'])
       end
     end
+
+    context 'when --allow-duplicates' do
+      let(:results) { { stdout: "", exit_status: 0 } }
+      let(:processes) { 2 }
+      let(:common_options) do
+        { files: ['test'], allow_duplicates: true, first_is_1: false }
+      end
+      before do
+        allow(subject).to receive(:puts)
+        expect(subject).to receive(:load_runner).with("my_test_runner").and_return(ParallelTests::MyTestRunner::Runner)
+        allow(ParallelTests::MyTestRunner::Runner).to receive(:test_file_name).and_return("test")
+        expect(subject).to receive(:report_results).and_return(nil)
+      end
+
+      before do
+        expect(ParallelTests::MyTestRunner::Runner).to receive(:tests_in_groups).and_return(
+          [
+            ['foo'],
+            ['foo'],
+            ['bar']
+          ]
+        )
+      end
+
+      it "calls run_tests with --only-group" do
+        options = common_options.merge(count: processes, only_group: [2, 3], group_by: :filesize)
+        expect(subject).to receive(:run_tests).once.with(['foo'], 0, 1, options).and_return(results)
+        expect(subject).to receive(:run_tests).once.with(['bar'], 1, 1, options).and_return(results)
+        subject.run(['test', '-n', processes.to_s, '--allow-duplicates', '--only-group', '2,3', '-t', 'my_test_runner'])
+      end
+
+      it "calls run_tests with --first-is-1" do
+        options = common_options.merge(count: processes, first_is_1: true)
+        expect(subject).to receive(:run_tests).once.with(['foo'], 0, processes, options).and_return(results)
+        expect(subject).to receive(:run_tests).once.with(['foo'], 1, processes, options).and_return(results)
+        expect(subject).to receive(:run_tests).once.with(['bar'], 2, processes, options).and_return(results)
+        subject.run(['test', '-n', processes.to_s, '--first-is-1', '--allow-duplicates', '-t', 'my_test_runner'])
+      end
+    end
   end
 
   describe "#display_duration" do