diff --git a/VM/private_named_parameters_t01.dart b/VM/private_named_parameters_t01.dart
new file mode 100644
index 0000000000..567a815035
--- /dev/null
+++ b/VM/private_named_parameters_t01.dart
@@ -0,0 +1,188 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion We let users use a private name in a named parameter when the
+/// parameter also initializes or declares a field. The compiler removes the `_`
+/// from the argument name but keeps it for the corresponding field.
+///
+/// @description Check that private named parameters can be debugged.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=declaring-constructors,private-named-parameters
+
+import 'dart:developer';
+import 'package:vm_service/vm_service.dart';
+
+import '../../../../pkg/vm_service/test/common/service_test_common.dart';
+import '../../../../pkg/vm_service/test/common/test_helper.dart';
+import '../Utils/expect.dart';
+
+// AUTOGENERATED START
+//
+// Update these constants by running:
+//
+// dart pkg/vm_service/test/update_line_numbers.dart tests/co19/src/VM/private_named_parameters_t01.dart
+//
+const LINE_A = 37;
+const LINE_B = 41;
+const LINE_C = 45;
+const LINE_D = 46;
+const LINE_E = 47;
+// AUTOGENERATED END
+
+class C1({var String _x});              // LINE_A
+
+class C2 {
+  String _x;
+  C2({required this._x});               // LINE_B
+}
+
+class C3 {
+  int _x, _y;
+  C3({required this._x}) : _y = _x + 1; // LINE_C
+}
+
+void testeeMain() {
+  debugger();           // LINE_D
+  C1(x: "xxx");         // LINE_E
+  C2(x: "yyy");         // LINE_F
+  C3(x: 1);             // LINE_G
+}
+
+final tests = <IsolateTest>[
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(LINE_D),
+  stepInto,
+  stoppedAtLine(LINE_E),
+  stepInto,
+  stoppedAtLine(LINE_A),
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals("null", xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals("null", xRef2.valueAsString);
+  },
+  stepInto,
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals('xxx', xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals('xxx', xRef2.valueAsString);
+    final xRef3 = await service.evaluateInFrame(isolateId, 0, 'x');
+    Expect.isTrue(xRef3 is ErrorRef);
+    final xRef4 = await service.evaluateInFrame(isolateId, 0, 'this.x');
+    Expect.isTrue(xRef4 is ErrorRef);
+  },
+  stepInto,
+  stoppedAtLine(LINE_F),
+  stepInto,
+  stoppedAtLine(LINE_B),
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals("null", xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals("null", xRef2.valueAsString);
+  },
+  stepInto,
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals('yyy', xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals('yyy', xRef2.valueAsString);
+    final xRef3 = await service.evaluateInFrame(isolateId, 0, 'x');
+    Expect.isTrue(xRef3 is ErrorRef);
+    final xRef4 = await service.evaluateInFrame(isolateId, 0, 'this.x');
+    Expect.isTrue(xRef4 is ErrorRef);
+  },
+
+  stepInto,
+  stoppedAtLine(LINE_G),
+  stepInto,
+  stoppedAtLine(LINE_C),
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals("null", xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals("null", xRef2.valueAsString);
+    final xRef3 =
+        await service.evaluateInFrame(isolateId, 0, '_y') as InstanceRef;
+    Expect.equals("null", xRef3.valueAsString);
+    final xRef4 =
+        await service.evaluateInFrame(isolateId, 0, 'this._y') as InstanceRef;
+    Expect.equals("null", xRef4.valueAsString);
+  },
+  stepInto,
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals('1', xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals('1', xRef2.valueAsString);
+    final xRef3 =
+        await service.evaluateInFrame(isolateId, 0, '_y') as InstanceRef;
+    Expect.equals('null', xRef3.valueAsString);
+    final xRef4 =
+        await service.evaluateInFrame(isolateId, 0, 'this._y') as InstanceRef;
+    Expect.equals('null', xRef3.valueAsString);
+
+    final xRef5 = await service.evaluateInFrame(isolateId, 0, 'x');
+    Expect.isTrue(xRef5 is ErrorRef);
+    final xRef6 = await service.evaluateInFrame(isolateId, 0, 'this.x');
+    Expect.isTrue(xRef6 is ErrorRef);
+    final xRef7 = await service.evaluateInFrame(isolateId, 0, 'y');
+    Expect.isTrue(xRef7 is ErrorRef);
+    final xRef8 = await service.evaluateInFrame(isolateId, 0, 'this.y');
+    Expect.isTrue(xRef8 is ErrorRef);
+  },
+  stepInto,
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+    final xRef1 =
+        await service.evaluateInFrame(isolateId, 0, '_x') as InstanceRef;
+    Expect.equals('1', xRef1.valueAsString);
+    final xRef2 =
+        await service.evaluateInFrame(isolateId, 0, 'this._x') as InstanceRef;
+    Expect.equals('1', xRef2.valueAsString);
+    final xRef3 =
+        await service.evaluateInFrame(isolateId, 0, '_y') as InstanceRef;
+    Expect.equals('2', xRef3.valueAsString);
+    final xRef4 =
+        await service.evaluateInFrame(isolateId, 0, 'this._y') as InstanceRef;
+    Expect.equals('2', xRef3.valueAsString);
+
+    final xRef5 = await service.evaluateInFrame(isolateId, 0, 'x');
+    Expect.isTrue(xRef5 is ErrorRef);
+    final xRef6 = await service.evaluateInFrame(isolateId, 0, 'this.x');
+    Expect.isTrue(xRef6 is ErrorRef);
+    final xRef7 = await service.evaluateInFrame(isolateId, 0, 'y');
+    Expect.isTrue(xRef7 is ErrorRef);
+    final xRef8 = await service.evaluateInFrame(isolateId, 0, 'this.y');
+    Expect.isTrue(xRef8 is ErrorRef);
+  },
+];
+
+void main([args = const <String>[]]) => runIsolateTests(
+  args,
+  tests,
+  'private_named_parameters_t01.dart',
+  pauseOnExit: true,
+  testeeConcurrent: testeeMain,
+);
diff --git a/VM/private_named_parameters_t02.dart b/VM/private_named_parameters_t02.dart
new file mode 100644
index 0000000000..0cf618b501
--- /dev/null
+++ b/VM/private_named_parameters_t02.dart
@@ -0,0 +1,69 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion We let users use a private name in a named parameter when the
+/// parameter also initializes or declares a field. The compiler removes the `_`
+/// from the argument name but keeps it for the corresponding field.
+///
+/// @description Check that private named parameters are allowed in VM
+/// expression evaluation.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=declaring-constructors,private-named-parameters
+
+import 'dart:developer';
+
+import 'package:vm_service/vm_service.dart';
+
+import '../../../../pkg/vm_service/test/common/service_test_common.dart';
+import '../../../../pkg/vm_service/test/common/test_helper.dart';
+import '../Utils/expect.dart';
+
+class C1({var String _x});
+
+class C2 {
+  String _x;
+  C2({required this._x});
+}
+
+void testeeMain() {
+  final c1 = C1(x: "one");
+  final c2 = C2(x: "two");
+  debugger();
+}
+
+final tests = <IsolateTest>[
+  hasStoppedAtBreakpoint,
+
+  // Test interaction of expression evaluation with private named parameters.
+  (VmService service, IsolateRef isolateRef) async {
+    final isolateId = isolateRef.id!;
+
+    InstanceRef response =
+       await service.evaluateInFrame(isolateId, 0, 'c1._x') as InstanceRef;
+    Expect.equals('one', response.valueAsString);
+
+    response =
+        await service.evaluateInFrame(isolateId, 0, 'c2._x') as InstanceRef;
+    Expect.equals('two', response.valueAsString);
+
+    response =
+        await service.evaluateInFrame(isolateId, 0, 'C1(x: "zero")._x')
+            as InstanceRef;
+    Expect.equals('zero', response.valueAsString);
+
+    response =
+        await service.evaluateInFrame(isolateId, 0, 'C2(x: "0")._x')
+            as InstanceRef;
+    Expect.equals('0', response.valueAsString);
+  },
+];
+
+void main([args = const <String>[]]) => runIsolateTests(
+  args,
+  tests,
+  'private_named_parameters_t02.dart',
+  pauseOnExit: true,
+  testeeConcurrent: testeeMain,
+);