diff --git a/lib/src/finite_state_machine.dart b/lib/src/finite_state_machine.dart
index c090e1477..0f5387784 100644
--- a/lib/src/finite_state_machine.dart
+++ b/lib/src/finite_state_machine.dart
@@ -179,8 +179,19 @@ class FiniteStateMachine<StateIdentifier> {
 
     for (final state in _states) {
       for (final entry in state.events.entries) {
-        figure.addTransitions(state.identifier.toString(),
-            entry.value.toString(), entry.key.name);
+        figure.addTransitions(
+          state.identifier.toString(),
+          entry.value.toString(),
+          entry.key.name,
+        );
+      }
+
+      if (state.defaultNextState != state.identifier) {
+        figure.addTransitions(
+          state.identifier.toString(),
+          state.defaultNextState.toString(),
+          '(default)',
+        );
       }
     }
     figure.writeToFile();
diff --git a/test/fsm_test.dart b/test/fsm_test.dart
index 7c4088656..c906b093c 100644
--- a/test/fsm_test.dart
+++ b/test/fsm_test.dart
@@ -54,6 +54,28 @@ class TestModule extends Module {
   }
 }
 
+class DefaultStateFsmMod extends Module {
+  late final FiniteStateMachine<MyStates> _fsm;
+  DefaultStateFsmMod(Logic reset) {
+    reset = addInput('reset', reset);
+    final clk = SimpleClockGenerator(10).clk;
+    final b = addOutput('b', width: 8);
+
+    _fsm = FiniteStateMachine<MyStates>(clk, reset, MyStates.state1, [
+      State(
+        MyStates.state1,
+        events: {Const(0): MyStates.state2},
+        actions: [b < 1],
+        defaultNextState: MyStates.state3,
+      ),
+      State(MyStates.state2, events: {}, actions: [b < 2]),
+      State(MyStates.state3,
+          events: {}, actions: [b < 3], defaultNextState: MyStates.state4),
+      State(MyStates.state4, events: {}, actions: [b < 4]),
+    ]);
+  }
+}
+
 enum LightStates { northFlowing, northSlowing, eastFlowing, eastSlowing }
 
 enum TrafficPresence {
@@ -226,6 +248,35 @@ void main() {
       verifyMermaidStateDiagram(_simpleFSMPath);
     });
 
+    test('default next state fsm', () async {
+      final pipem = DefaultStateFsmMod(Logic());
+
+      await pipem.build();
+
+      final vectors = [
+        Vector({'reset': 1}, {}),
+        Vector({'reset': 0}, {'b': 1}),
+        Vector({'reset': 0}, {'b': 3}),
+        Vector({'reset': 0}, {'b': 4}),
+        Vector({'reset': 0}, {'b': 4}),
+      ];
+      await SimCompare.checkFunctionalVector(pipem, vectors);
+      SimCompare.checkIverilogVector(pipem, vectors);
+
+      if (!kIsWeb) {
+        const fsmPath = '$_tmpDir/default_next_state_fsm.md';
+        pipem._fsm.generateDiagram(outputPath: fsmPath);
+
+        final mermaid = File(fsmPath).readAsStringSync();
+        expect(mermaid, contains('state2'));
+        expect(mermaid, contains('state3'));
+        expect(mermaid, contains('state4'));
+        expect(mermaid, contains('(default)'));
+
+        verifyMermaidStateDiagram(fsmPath);
+      }
+    });
+
     test('traffic light fsm', () async {
       final pipem = TrafficTestModule(Logic(width: 2), Logic());
       await pipem.build();