Ada Wong is a character in Resident Evil, a survival horror video game series created by the Japanese company Capcom. She was introduced as a supporting character in Resident Evil 2 (1998), before becoming a playable character in Resident Evil 4 (2005). Ada is a mysterious spy and mercenary who is often hired by villains, such as Albert Wesker, though she has betrayed her employers for her own agendas and saved protagonist Leon S. Kennedy from dire situations.

Resident Evil, or Biohazard in Japan and parts of Southeast Asia, is a Japanese horror game series and media franchise created by Capcom. It consists of survival horror, third-person shooter and first-person shooter games, with players typically surviving in environments inhabited by zombies and other frightening creatures. The franchise has expanded into other media, including a live-action film series, animated films, television series, comic books, novels, audio dramas and merchandise. Resident Evil is the highest-grossing horror franchise.