diff --git a/crates/dash_middle/src/interner.rs b/crates/dash_middle/src/interner.rs
index cfd22883..ed9920ff 100644
--- a/crates/dash_middle/src/interner.rs
+++ b/crates/dash_middle/src/interner.rs
@@ -254,6 +254,8 @@ pub mod sym {
                 isConcatSpreadable,
                 zero: "0",
                 one: "1",
+                getPrototypeOf,
+                isPrototypeOf
             }
         ]
     }
diff --git a/crates/dash_vm/src/js_std/object.rs b/crates/dash_vm/src/js_std/object.rs
index f6d69d95..1464bd6c 100644
--- a/crates/dash_vm/src/js_std/object.rs
+++ b/crates/dash_vm/src/js_std/object.rs
@@ -7,7 +7,7 @@ use crate::value::function::native::CallContext;
 use crate::value::object::{NamedObject, Object, PropertyKey, PropertyValue};
 use crate::value::ops::conversions::ValueConversion;
 use crate::value::root_ext::RootErrExt;
-use crate::value::{Root, Value, ValueContext};
+use crate::value::{Root, Typeof, Value, ValueContext};
 
 pub fn constructor(cx: CallContext) -> Result<Value, Value> {
     match cx.args.first() {
@@ -190,3 +190,28 @@ pub fn entries(cx: CallContext) -> Result<Value, Value> {
     let entries = Array::from_vec(cx.scope, entries);
     Ok(Value::Object(cx.scope.register(entries)))
 }
+
+pub fn get_prototype_of(cx: CallContext) -> Result<Value, Value> {
+    let obj = cx.args.first().unwrap_or_undefined().to_object(cx.scope)?;
+    obj.get_prototype(cx.scope)
+}
+
+pub fn is_prototype_of(cx: CallContext) -> Result<Value, Value> {
+    let target_proto = Value::Object(cx.this.to_object(cx.scope)?);
+    let mut this_proto = cx.args.first().unwrap_or_undefined();
+    if this_proto.type_of() != Typeof::Object {
+        return Ok(Value::Boolean(false));
+    }
+
+    loop {
+        if this_proto == target_proto {
+            return Ok(Value::Boolean(true));
+        }
+
+        this_proto = match this_proto {
+            Value::Object(obj) => obj.get_prototype(cx.scope)?,
+            Value::External(obj) => obj.inner.get_prototype(cx.scope)?,
+            _ => return Ok(Value::Boolean(false)),
+        };
+    }
+}
diff --git a/crates/dash_vm/src/lib.rs b/crates/dash_vm/src/lib.rs
index 028450cb..ee11de19 100644
--- a/crates/dash_vm/src/lib.rs
+++ b/crates/dash_vm/src/lib.rs
@@ -235,6 +235,7 @@ impl Vm {
                 (sym::defineProperty, scope.statics.object_define_property.clone()),
                 (sym::entries, scope.statics.object_entries.clone()),
                 (sym::assign, scope.statics.object_assign.clone()),
+                (sym::getPrototypeOf, scope.statics.object_get_prototype_of.clone()),
             ],
             [],
             [],
@@ -249,6 +250,7 @@ impl Vm {
             [
                 (sym::toString, scope.statics.object_to_string.clone()),
                 (sym::hasOwnProperty, scope.statics.object_has_own_property.clone()),
+                (sym::isPrototypeOf, scope.statics.object_is_prototype_of.clone()),
             ],
             [],
             [],
diff --git a/crates/dash_vm/src/statics.rs b/crates/dash_vm/src/statics.rs
index 038f24ee..6d68b16f 100644
--- a/crates/dash_vm/src/statics.rs
+++ b/crates/dash_vm/src/statics.rs
@@ -77,6 +77,8 @@ pub struct Statics {
     pub object_define_property: Handle<dyn Object>,
     pub object_assign: Handle<dyn Object>,
     pub object_entries: Handle<dyn Object>,
+    pub object_get_prototype_of: Handle<dyn Object>,
+    pub object_is_prototype_of: Handle<dyn Object>,
     pub number_ctor: Handle<dyn Object>,
     pub number_prototype: Handle<dyn Object>,
     pub number_tostring: Handle<dyn Object>,
@@ -288,6 +290,8 @@ impl Statics {
             object_define_property: function(gc, sym::defineProperty, js_std::object::define_property),
             object_assign: function(gc, sym::assign, js_std::object::assign),
             object_entries: function(gc, sym::entries, js_std::object::entries),
+            object_get_prototype_of: function(gc, sym::getPrototypeOf, js_std::object::get_prototype_of),
+            object_is_prototype_of: function(gc, sym::isPrototypeOf, js_std::object::is_prototype_of),
             number_ctor: function(gc, sym::Number, js_std::number::constructor),
             number_prototype: builtin_object(gc, BoxedNumber::with_obj(0.0, NamedObject::null())),
             number_tostring: function(gc, sym::toString, js_std::number::to_string),
diff --git a/crates/dash_vm/src/test/mod.rs b/crates/dash_vm/src/test/mod.rs
index f9c38ff3..72846250 100644
--- a/crates/dash_vm/src/test/mod.rs
+++ b/crates/dash_vm/src/test/mod.rs
@@ -1,5 +1,4 @@
 use std::ptr;
-use std::rc::Rc;
 
 use dash_middle::interner::sym;
 use dash_optimizer::OptLevel;
diff --git a/crates/dash_vm/src/value/mod.rs b/crates/dash_vm/src/value/mod.rs
index 777ae364..65be4767 100755
--- a/crates/dash_vm/src/value/mod.rs
+++ b/crates/dash_vm/src/value/mod.rs
@@ -565,7 +565,7 @@ impl Value {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum Typeof {
     Undefined,
     Object,