diff --git a/src/env-inl.h b/src/env-inl.h
index 8107311ba70ca6..b27c5ec47b02bc 100644
--- a/src/env-inl.h
+++ b/src/env-inl.h
@@ -199,7 +199,7 @@ inline Environment::AsyncCallbackScope::~AsyncCallbackScope() {
   env_->makecallback_cntr_--;
 }
 
-inline bool Environment::AsyncCallbackScope::in_makecallback() {
+inline bool Environment::AsyncCallbackScope::in_makecallback() const {
   return env_->makecallback_cntr_ > 1;
 }
 
diff --git a/src/env.h b/src/env.h
index fa4b289f314e16..96bbd3ce5c9db1 100644
--- a/src/env.h
+++ b/src/env.h
@@ -439,7 +439,7 @@ class Environment {
     AsyncCallbackScope() = delete;
     explicit AsyncCallbackScope(Environment* env);
     ~AsyncCallbackScope();
-    inline bool in_makecallback();
+    inline bool in_makecallback() const;
 
    private:
     Environment* env_;