Mario Tennis is a 2000 sports video game developed by Camelot Software Planning and published by Nintendo for the Nintendo 64 (N64). Following Mario's Tennis, it is the second game in the Mario Tennis series. The game is known for being the introduction of Luigi's arch-rival, Waluigi, and the re-introduction of Princess Daisy and Birdo.

Camelot also developed a Game Boy Color (GBC) version, which was published under the same title in Western regions and as Mario Tennis GB in Japan.

The N64 version was re-released on the Wii and Wii U Virtual Console, and on the Nintendo Switch Online + Expansion Pack, in 2010, 2015, and 2021 respectively; the GBC version was re-released on the Nintendo 3DS Virtual Console in 2014, and on the Nintendo Switch Online service in 2024.