diff --git a/core/src/main/resources/org/teavm/backend/javascript/reflection.js b/core/src/main/resources/org/teavm/backend/javascript/reflection.js
index f3172ff67..c8cb67944 100644
--- a/core/src/main/resources/org/teavm/backend/javascript/reflection.js
+++ b/core/src/main/resources/org/teavm/backend/javascript/reflection.js
@@ -44,3 +44,4 @@ let $rt_castToClass = (obj, cls) => {
     }
     return obj;
 }
+let $rt_instanceOfOrNull = (obj, cls) => obj === null || obj instanceof cls;
\ No newline at end of file
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JS.java b/jso/impl/src/main/java/org/teavm/jso/impl/JS.java
index 8c35d51f9..03ec6ff9d 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JS.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JS.java
@@ -709,6 +709,10 @@ final class JS {
     @NoSideEffects
     public static native boolean instanceOf(JSObject obj, JSObject cls);
 
+    @InjectedBy(JSNativeInjector.class)
+    @NoSideEffects
+    public static native boolean instanceOfOrNull(JSObject obj, JSObject cls);
+
     @InjectedBy(JSNativeInjector.class)
     @NoSideEffects
     public static native boolean isPrimitive(JSObject obj, JSObject primitive);
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSClassProcessor.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSClassProcessor.java
index df0d8fb3a..ba0b970a0 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSClassProcessor.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSClassProcessor.java
@@ -578,7 +578,7 @@ class JSClassProcessor {
         var primitiveType = getPrimitiveType(targetClassName);
         var invoke = new InvokeInstruction();
         invoke.setType(InvocationType.SPECIAL);
-        invoke.setMethod(primitiveType != null ? JSMethods.IS_PRIMITIVE : JSMethods.INSTANCE_OF);
+        invoke.setMethod(primitiveType != null ? JSMethods.IS_PRIMITIVE : JSMethods.INSTANCE_OF_OR_NULL);
         var secondArg = primitiveType != null
                 ? marshaller.addJsString(primitiveType, location)
                 : marshaller.classRef(targetClassName, location);
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSMethods.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSMethods.java
index aad726d40..1f0ade807 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSMethods.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSMethods.java
@@ -127,6 +127,8 @@ final class JSMethods {
 
     public static final MethodReference INSTANCE_OF = new MethodReference(JS.class, "instanceOf", JSObject.class,
             JSObject.class, boolean.class);
+    public static final MethodReference INSTANCE_OF_OR_NULL = new MethodReference(JS.class, "instanceOfOrNull",
+            JSObject.class, JSObject.class, boolean.class);
     public static final MethodReference IS_PRIMITIVE = new MethodReference(JS.class, "isPrimitive", JSObject.class,
             JSObject.class, boolean.class);
     public static final MethodReference THROW_CCE_IF_FALSE = new MethodReference(JS.class, "throwCCEIfFalse",
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
index f3a30337d..511435faf 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
@@ -215,6 +215,14 @@ public class JSNativeInjector implements Injector, DependencyPlugin {
                 }
                 break;
             }
+            case "instanceOfOrNull": {
+                writer.appendFunction("$rt_instanceOfOrNull").append("(");
+                context.writeExpr(context.getArgument(0), Precedence.min());
+                writer.append(",").ws();
+                context.writeExpr(context.getArgument(1), Precedence.min());
+                writer.append(")");
+                break;
+            }
             case "isPrimitive": {
                 if (context.getPrecedence().ordinal() >= Precedence.CONDITIONAL.ordinal()) {
                     writer.append("(");
diff --git a/tests/src/test/java/org/teavm/jso/test/InstanceOfTest.java b/tests/src/test/java/org/teavm/jso/test/InstanceOfTest.java
index 82b7bc1e5..d18e3f5cb 100644
--- a/tests/src/test/java/org/teavm/jso/test/InstanceOfTest.java
+++ b/tests/src/test/java/org/teavm/jso/test/InstanceOfTest.java
@@ -17,6 +17,7 @@ package org.teavm.jso.test;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import org.junit.Test;
@@ -89,6 +90,9 @@ public class InstanceOfTest {
         } catch (ClassCastException e) {
             // expected
         }
+
+        var d = (ClassWithConstructor) returnNull();
+        assertNull(d);
     }
 
     private Object callCreateClassWithConstructor() {
@@ -98,6 +102,9 @@ public class InstanceOfTest {
     @JSBody(script = "return new ClassWithConstructor();")
     private static native JSObject createClassWithConstructor();
 
+    @JSBody(script = "return null;")
+    private static native JSObject returnNull();
+
     private Object callCreateNumber() {
         return createNumber();
     }
@@ -111,7 +118,7 @@ public class InstanceOfTest {
     }
 
     @JSClass(transparent = true)
-    abstract class C implements JSObject {
+    static abstract class C implements JSObject {
         @JSProperty
         public abstract int getFoo();
     }