Hyperdimension Neptunia (超次元ゲイム ネプテューヌ, Chōjigen Geimu Neputyūnu, lit. "Super Dimensional Game Neptune") is a series of role-playing video games produced by Compile Heart and Idea Factory, which revolves around and parodies the real-life video gaming industry and other forms of Japanese culture. The series has also branched off into a manga, light novel and anime media franchise series.

The series debuted in Japan on August 19, 2010, with the video game of the same name for the PlayStation 3, and received sequels: Hyperdimension Neptunia mk2 (2011), Hyperdimension Neptunia Victory (2012), and Megadimension Neptunia VII (2015) as the last of the main series. All the main games have been remade (the first three as "Re;Birth") and since then multiple spin-off and crossover games have also been released for various platforms.

An anime television series adaptation, titled Hyperdimension Neptunia: The Animation, aired in Japan between July and September 2013. An OVA, titled Nepu no Natsuyasumi, was released in July 2019. A second OVA, titled Nep Nep Darake no Festival, was released in October 2022, and third OVA, titled Hidamari no Little Purple, was released in April 2023.