Resident Evil 4 is a 2005 survival horror game developed and published by Capcom for the GameCube. Players control the special agent Leon S. Kennedy on a mission to rescue the US president's daughter, Ashley Graham, who has been kidnapped by a religious cult in rural Spain. Leon fights hordes of enemies infected by a mind-controlling parasite and reunites with the spy Ada Wong. In a departure from the fixed camera angles and slower gameplay of previous Resident Evil games, Resident Evil 4 features a dynamic camera system and action-oriented gameplay.

Development on Resident Evil 4 began for the PlayStation 2 in 1999. Four proposed versions were discarded; the first was directed by Hideki Kamiya, but series creator Shinji Mikami felt it was too great a departure from the previous games, so it was spun off as Devil May Cry (2001). Other versions were scrapped until Mikami took directorial duties for what became the final version. The game was announced as part of the Capcom Five, a collaboration between Capcom and Nintendo to create five exclusives for the GameCube.

Resident Evil 4 garnered acclaim for its story, gameplay, graphics, voice acting, and characters, and is cited as one of the best video games of all time, winning multiple Game of the Year awards in 2005. It was ported to numerous formats, and became a cross-platform hit, selling 12.3 million units by December 2022. It influenced the evolution of the survival horror and third-person genres, popularizing the "over-the-shoulder" third-person view used in games such as Gears of War, Dead Space, and The Last of Us. Its successor, Resident Evil 5, was released in 2009. A remake of Resident Evil 4 was released in 2023.