diff --git a/crates/vm/src/builtins/object.rs b/crates/vm/src/builtins/object.rs
index ca208790f4..879c287fdb 100644
--- a/crates/vm/src/builtins/object.rs
+++ b/crates/vm/src/builtins/object.rs
@@ -1,4 +1,4 @@
-use super::{PyDictRef, PyList, PyStr, PyStrRef, PyType, PyTypeRef};
+use super::{PyDictRef, PyInt, PyList, PyStr, PyStrRef, PyType, PyTypeRef};
 use crate::common::hash::PyHash;
 use crate::types::PyTypeFlags;
 use crate::{
@@ -577,6 +577,11 @@ impl PyBaseObject {
 
     #[pymethod]
     fn __sizeof__(zelf: PyObjectRef) -> usize {
+        if let Some(int) = zelf.downcast_ref::<PyInt>() {
+            let bits = int.as_bigint().bits();
+            return std::mem::size_of::<PyInt>() + (((bits + 7) & !7) / 8) as usize;
+        }
+
         zelf.class().slots.basicsize
     }
 }
diff --git a/extra_tests/snippets/builtin_object.py b/extra_tests/snippets/builtin_object.py
index 64486e1673..98c78c679f 100644
--- a/extra_tests/snippets/builtin_object.py
+++ b/extra_tests/snippets/builtin_object.py
@@ -32,3 +32,6 @@ class MyObject:
     0: "ab",
 }
 assert "ab ab" == "{k[0]} {vv}".format(k=d, vv=d[0])
+
+big = 1223456789812391231291231231231212312312312312312312321321321321312312321123123123199129391239219394923912949213021949302194942130123949203912430392402139210492139123012940219394923942395943856228368385
+assert object.__sizeof__(big) >= big.__sizeof__()