The 3rd Birthday is a role-playing shooter developed by HexaDrive and published by Square Enix for the PlayStation Portable. It was released in Japan in 2010 and in North America and Europe in 2011. The game is the third entry in the Parasite Eve video game series, based on the titular Japanese novel, and a spin-off, having only a loose connection to events from past games. The game features a third-person shooter-based combat system with role-playing mechanics. A key mechanic is the Overdive ability, which allows the player to possess pre-positioned human allies and inflict damage upon enemies.

Parasite Eve is a Japanese science fiction horror novel by Hideaki Sena, first published by Kadokawa in 1995. The book was published in North America by Vertical, Inc. in 2005.