diff --git a/native_mate/converter.cc b/native_mate/converter.cc
index c7cf96c3042c..7554ae787c1e 100644
--- a/native_mate/converter.cc
+++ b/native_mate/converter.cc
@@ -25,6 +25,8 @@ Handle<Value> Converter<bool>::ToV8(Isolate* isolate, bool val) {
 }
 
 bool Converter<bool>::FromV8(Isolate* isolate, Handle<Value> val, bool* out) {
+  if (!val->IsBoolean())
+    return false;
   *out = val->BooleanValue();
   return true;
 }