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 created and developed by Compile Heart and Idea Factory. The series debuted in Japan on August 19, 2010, with the video game of the same name for the PlayStation 3, which received two sequels, Hyperdimension Neptunia mk2 and Hyperdimension Neptunia Victory. All three games were remade for PlayStation Vita and Windows. Another sequel, titled Megadimension Neptunia VII, as well as multiple spin-off and crossover games were released for various platforms since then. It has also branched off into a manga, light novel and anime media franchise series.

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.