diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1f4fb57515e..3fc27bd4f34 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -35660,7 +35660,7 @@ namespace ts {
             const implementedTypeNodes = getEffectiveImplementsTypeNodes(node);
             if (implementedTypeNodes) {
                 for (const typeRefNode of implementedTypeNodes) {
-                    if (!isEntityNameExpression(typeRefNode.expression)) {
+                    if (!isEntityNameExpression(typeRefNode.expression) || isOptionalChain(typeRefNode.expression)) {
                         error(typeRefNode.expression, Diagnostics.A_class_can_only_implement_an_identifier_Slashqualified_name_with_optional_type_arguments);
                     }
                     checkTypeReferenceNode(typeRefNode);
@@ -36009,7 +36009,7 @@ namespace ts {
                 checkObjectTypeForDuplicateDeclarations(node);
             }
             forEach(getInterfaceBaseTypeNodes(node), heritageElement => {
-                if (!isEntityNameExpression(heritageElement.expression)) {
+                if (!isEntityNameExpression(heritageElement.expression) || isOptionalChain(heritageElement.expression)) {
                     error(heritageElement.expression, Diagnostics.An_interface_can_only_extend_an_identifier_Slashqualified_name_with_optional_type_arguments);
                 }
                 checkTypeReferenceNode(heritageElement);
diff --git a/tests/baselines/reference/classExtendingOptionalChain.errors.txt b/tests/baselines/reference/classExtendingOptionalChain.errors.txt
new file mode 100644
index 00000000000..2f4d321e8f9
--- /dev/null
+++ b/tests/baselines/reference/classExtendingOptionalChain.errors.txt
@@ -0,0 +1,16 @@
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts(9,21): error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.
+
+
+==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts (1 errors) ====
+    namespace A {
+        export class B {}
+    }
+    
+    // ok
+    class C1 extends A?.B {}
+    
+    // error
+    class C2 implements A?.B {}
+                        ~~~~
+!!! error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendingOptionalChain.js b/tests/baselines/reference/classExtendingOptionalChain.js
new file mode 100644
index 00000000000..c715a9dedcc
--- /dev/null
+++ b/tests/baselines/reference/classExtendingOptionalChain.js
@@ -0,0 +1,51 @@
+//// [classExtendingOptionalChain.ts]
+namespace A {
+    export class B {}
+}
+
+// ok
+class C1 extends A?.B {}
+
+// error
+class C2 implements A?.B {}
+
+
+//// [classExtendingOptionalChain.js]
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var A;
+(function (A) {
+    var B = /** @class */ (function () {
+        function B() {
+        }
+        return B;
+    }());
+    A.B = B;
+})(A || (A = {}));
+// ok
+var C1 = /** @class */ (function (_super) {
+    __extends(C1, _super);
+    function C1() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return C1;
+}((A === null || A === void 0 ? void 0 : A.B)));
+// error
+var C2 = /** @class */ (function () {
+    function C2() {
+    }
+    return C2;
+}());
diff --git a/tests/baselines/reference/classExtendingOptionalChain.symbols b/tests/baselines/reference/classExtendingOptionalChain.symbols
new file mode 100644
index 00000000000..2b83fa613dd
--- /dev/null
+++ b/tests/baselines/reference/classExtendingOptionalChain.symbols
@@ -0,0 +1,22 @@
+=== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts ===
+namespace A {
+>A : Symbol(A, Decl(classExtendingOptionalChain.ts, 0, 0))
+
+    export class B {}
+>B : Symbol(B, Decl(classExtendingOptionalChain.ts, 0, 13))
+}
+
+// ok
+class C1 extends A?.B {}
+>C1 : Symbol(C1, Decl(classExtendingOptionalChain.ts, 2, 1))
+>A?.B : Symbol(A.B, Decl(classExtendingOptionalChain.ts, 0, 13))
+>A : Symbol(A, Decl(classExtendingOptionalChain.ts, 0, 0))
+>B : Symbol(A.B, Decl(classExtendingOptionalChain.ts, 0, 13))
+
+// error
+class C2 implements A?.B {}
+>C2 : Symbol(C2, Decl(classExtendingOptionalChain.ts, 5, 24))
+>A?.B : Symbol(A.B, Decl(classExtendingOptionalChain.ts, 0, 13))
+>A : Symbol(A, Decl(classExtendingOptionalChain.ts, 0, 0))
+>B : Symbol(A.B, Decl(classExtendingOptionalChain.ts, 0, 13))
+
diff --git a/tests/baselines/reference/classExtendingOptionalChain.types b/tests/baselines/reference/classExtendingOptionalChain.types
new file mode 100644
index 00000000000..33a498fcab6
--- /dev/null
+++ b/tests/baselines/reference/classExtendingOptionalChain.types
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts ===
+namespace A {
+>A : typeof A
+
+    export class B {}
+>B : B
+}
+
+// ok
+class C1 extends A?.B {}
+>C1 : C1
+>A?.B : A.B
+>A : typeof A
+>B : typeof A.B
+
+// error
+class C2 implements A?.B {}
+>C2 : C2
+>A : typeof A
+
diff --git a/tests/baselines/reference/interfaceExtendingOptionalChain.errors.txt b/tests/baselines/reference/interfaceExtendingOptionalChain.errors.txt
new file mode 100644
index 00000000000..810dbd4b733
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingOptionalChain.errors.txt
@@ -0,0 +1,12 @@
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts(5,22): error TS2499: An interface can only extend an identifier/qualified-name with optional type arguments.
+
+
+==== tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts (1 errors) ====
+    namespace Foo {
+        export class Bar {}
+    }
+    
+    interface C1 extends Foo?.Bar {}
+                         ~~~~~~~~
+!!! error TS2499: An interface can only extend an identifier/qualified-name with optional type arguments.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/interfaceExtendingOptionalChain.js b/tests/baselines/reference/interfaceExtendingOptionalChain.js
new file mode 100644
index 00000000000..5e31589ec94
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingOptionalChain.js
@@ -0,0 +1,18 @@
+//// [interfaceExtendingOptionalChain.ts]
+namespace Foo {
+    export class Bar {}
+}
+
+interface C1 extends Foo?.Bar {}
+
+
+//// [interfaceExtendingOptionalChain.js]
+var Foo;
+(function (Foo) {
+    var Bar = /** @class */ (function () {
+        function Bar() {
+        }
+        return Bar;
+    }());
+    Foo.Bar = Bar;
+})(Foo || (Foo = {}));
diff --git a/tests/baselines/reference/interfaceExtendingOptionalChain.symbols b/tests/baselines/reference/interfaceExtendingOptionalChain.symbols
new file mode 100644
index 00000000000..548ae62afa4
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingOptionalChain.symbols
@@ -0,0 +1,14 @@
+=== tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts ===
+namespace Foo {
+>Foo : Symbol(Foo, Decl(interfaceExtendingOptionalChain.ts, 0, 0))
+
+    export class Bar {}
+>Bar : Symbol(Bar, Decl(interfaceExtendingOptionalChain.ts, 0, 15))
+}
+
+interface C1 extends Foo?.Bar {}
+>C1 : Symbol(C1, Decl(interfaceExtendingOptionalChain.ts, 2, 1))
+>Foo?.Bar : Symbol(Foo.Bar, Decl(interfaceExtendingOptionalChain.ts, 0, 15))
+>Foo : Symbol(Foo, Decl(interfaceExtendingOptionalChain.ts, 0, 0))
+>Bar : Symbol(Foo.Bar, Decl(interfaceExtendingOptionalChain.ts, 0, 15))
+
diff --git a/tests/baselines/reference/interfaceExtendingOptionalChain.types b/tests/baselines/reference/interfaceExtendingOptionalChain.types
new file mode 100644
index 00000000000..4d3eb2a937d
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingOptionalChain.types
@@ -0,0 +1,11 @@
+=== tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts ===
+namespace Foo {
+>Foo : typeof Foo
+
+    export class Bar {}
+>Bar : Bar
+}
+
+interface C1 extends Foo?.Bar {}
+>Foo : typeof Foo
+
diff --git a/tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts b/tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts
new file mode 100644
index 00000000000..261bb09e5ae
--- /dev/null
+++ b/tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingOptionalChain.ts
@@ -0,0 +1,9 @@
+namespace A {
+    export class B {}
+}
+
+// ok
+class C1 extends A?.B {}
+
+// error
+class C2 implements A?.B {}
diff --git a/tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts b/tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts
new file mode 100644
index 00000000000..767f3085d22
--- /dev/null
+++ b/tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendingOptionalChain.ts
@@ -0,0 +1,5 @@
+namespace Foo {
+    export class Bar {}
+}
+
+interface C1 extends Foo?.Bar {}