diff --git a/ets2panda/checker/ets/validateHelpers.cpp b/ets2panda/checker/ets/validateHelpers.cpp
index f3ad9a385b9c4e0619ab024c454748e9602ecc35..bd0a6ceb9b58027730f2ebde7db6aea0b71936a5 100644
--- a/ets2panda/checker/ets/validateHelpers.cpp
+++ b/ets2panda/checker/ets/validateHelpers.cpp
@@ -129,7 +129,8 @@ bool ETSChecker::ValidateBinaryExpressionIdentifier(ir::Identifier *const ident,
     const auto *const binaryExpr = ident->Parent()->AsBinaryExpression();
     bool isFinished = false;
 
-    if (binaryExpr->OperatorType() == lexer::TokenType::KEYW_INSTANCEOF && binaryExpr->Left() == ident) {
+    bool isInstanceOfKeyword = binaryExpr->OperatorType() == lexer::TokenType::KEYW_INSTANCEOF;
+    if (isInstanceOfKeyword && binaryExpr->Left() == ident) {
         if (!IsReferenceType(type)) {
             std::ignore =
                 TypeError(ident->Variable(), diagnostic::INSTANCEOF_NONOBJECT, {ident->Name()}, ident->Start());
@@ -145,6 +146,10 @@ bool ETSChecker::ValidateBinaryExpressionIdentifier(ir::Identifier *const ident,
         }
         isFinished = true;
     }
+    if (isInstanceOfKeyword && ident->Variable()->HasFlag(varbinder::VariableFlags::CLASS_OR_INTERFACE |
+                                                          varbinder::VariableFlags::TYPE_ALIAS)) {
+        LogError(diagnostic::WRONG_LEFT_OF_INSTANCEOF, {}, ident->Start());
+    }
     return isFinished;
 }
 
diff --git a/ets2panda/parser/ETSparserTypes.cpp b/ets2panda/parser/ETSparserTypes.cpp
index c88b813839c23e8add2f6c176521551081589d0f..2f51ebead2ac920669349a8f9eed8f6b0ed44457 100644
--- a/ets2panda/parser/ETSparserTypes.cpp
+++ b/ets2panda/parser/ETSparserTypes.cpp
@@ -514,6 +514,12 @@ bool ETSParser::ParseReadonlyInTypeAnnotation()
 ir::TypeNode *ETSParser::ParseTypeAnnotation(TypeAnnotationParsingOptions *options)
 {
     const auto startPos = Lexer()->GetToken().Start();
+    if ((*options &
+         (TypeAnnotationParsingOptions::DISALLOW_UNION | TypeAnnotationParsingOptions::ANNOTATION_NOT_ALLOW)) == 0 &&
+        Lexer()->TryEatTokenFromKeywordType(lexer::TokenType::KEYW_TYPEOF)) {
+        LogError(diagnostic::TYPEOF_IN_ANNOTATION);
+        return AllocBrokenType(Lexer()->GetToken().Loc());
+    }
     // if there is prefix readonly parameter type, change the return result to ETSTypeReference, like Readonly<>
     if (!Lexer()->TryEatTokenFromKeywordType(lexer::TokenType::KEYW_READONLY)) {
         return ParseTypeAnnotationNoPreferParam(options);
diff --git a/ets2panda/test/ast/parser/ets/instanceof_on_type.ets b/ets2panda/test/ast/parser/ets/instanceof_on_type.ets
new file mode 100644
index 0000000000000000000000000000000000000000..cb4b9dcc7b05ba006d5618998dd5107762e997e5
--- /dev/null
+++ b/ets2panda/test/ast/parser/ets/instanceof_on_type.ets
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class X {}
+type B = X
+
+let a = (new X()) instanceof Object
+let b = (new X()) instanceof X
+let c = X instanceof Object
+let d = X instanceof X
+let f = B instanceof Object
+
+/* @@? 21:9 Error SyntaxError: The left operand of 'instanceof' operator cannot be a type.  */
+/* @@? 22:9 Error SyntaxError: The left operand of 'instanceof' operator cannot be a type.  */
+/* @@? 23:9 Error SyntaxError: The left operand of 'instanceof' operator cannot be a type.  */
diff --git a/ets2panda/test/ast/parser/ets/typeof_in_annotation.ets b/ets2panda/test/ast/parser/ets/typeof_in_annotation.ets
new file mode 100644
index 0000000000000000000000000000000000000000..2ab98e4b5510f88e510b477c9f16a13dacdfec91
--- /dev/null
+++ b/ets2panda/test/ast/parser/ets/typeof_in_annotation.ets
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+let n1 = 42
+let s1 = "foo"
+let n2: typeof n1
+let s2: typeof s1
+
+/* @@? 18:16 Error SyntaxError: Result of 'typeof' operator is not supported to be used as type annotation.  */
+/* @@? 18:16 Error SyntaxError: Unexpected token 'n1'.  */
+/* @@? 19:16 Error SyntaxError: Result of 'typeof' operator is not supported to be used as type annotation.  */
+/* @@? 19:16 Error SyntaxError: Unexpected token 's1'.  */
diff --git a/ets2panda/util/diagnostic/syntax.yaml b/ets2panda/util/diagnostic/syntax.yaml
index d18a5f97664b29d5d399fcedacb9e97511b96771..71a315ef06eb33e988f96e4faa60c6af959e421b 100644
--- a/ets2panda/util/diagnostic/syntax.yaml
+++ b/ets2panda/util/diagnostic/syntax.yaml
@@ -1234,4 +1234,12 @@ syntax:
 
 - name: OPTIONAL_VARIABLE
   id: 306
-  message: "Optional variable is deprecated and no longer supported."
\ No newline at end of file
+  message: "Optional variable is deprecated and no longer supported."
+
+- name: TYPEOF_IN_ANNOTATION
+  id: 307
+  message: "Result of 'typeof' operator is not supported to be used as type annotation."
+
+- name: WRONG_LEFT_OF_INSTANCEOF
+  id: 308
+  message: "The left operand of 'instanceof' operator cannot be a type."