diff --git a/vm/src/stdlib/json.rs b/vm/src/stdlib/json.rs
index 64f59215b9..6c821e6a07 100644
--- a/vm/src/stdlib/json.rs
+++ b/vm/src/stdlib/json.rs
@@ -1,7 +1,7 @@
 use crate::obj::objiter;
 use crate::obj::objstr::PyStringRef;
 use crate::obj::{objbool, objtype::PyClassRef};
-use crate::pyobject::{IdProtocol, PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{IdProtocol, PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue, ThreadSafe};
 use crate::VirtualMachine;
 
 use num_bigint::BigInt;
@@ -19,6 +19,8 @@ struct JsonScanner {
     ctx: PyObjectRef,
 }
 
+impl ThreadSafe for JsonScanner {}
+
 impl PyValue for JsonScanner {
     fn class(vm: &VirtualMachine) -> PyClassRef {
         vm.class("_json", "make_scanner")