Who is Naruto's grandmother?

Answer 1

No one knows but Kushina Uzumaki and Minato Namikaze-deceased Jiraiya probably knows, and there's a good chance that Tsunade might. However, Kakashi knowing is something I doubt . . . .

Either way, whoever it is, they're dead; both Uzumaki and Namikaze clans are "gone".

Answer 2

It is widely believed that Tsunade is the grandmother of Naruto. This information has never been confirmed in the series however.

Answer 3

I think lady Tsunade.