[i]Caligula[/i] or ([i]The Caligula Effect[/i] in English) is a role-playing video game series developed by Aquaria and ported for English speaking audiences by ATLUS USA and NIS America.

The series consists of the following games:
* [[Caligula (game)|]] (turned into a 2018 anime of the same name, and remade as an updated game "Caligula: Overdose")
* [[Caligula 2]]