Ada Wong[a] is a character in Resident Evil (Biohazard in Japan), a survival horror video game series created by the Japanese company Capcom.

Over the course of the series, Ada is often hired to steal biological weapons for various organizations, although she betrays her employers on numerous occasions to save protagonist Leon S. Kennedy from dire situations.

Ada Wong is the pseudonym of a Chinese-American spy and mercenary who recurs as an antiheroine in Capcom's survival horror video game series Resident Evil.

[16][17] Introduced as a supporting character in Resident Evil 2 (1998),[8][18] Ada is hired by an unnamed organization to steal the G-virus mutagen developed by the Umbrella Corporation, a pharmaceutical company responsible for a zombie outbreak in the fictional American metropolitan area of Raccoon City.

[19][20] Ada meets and allies with rookie police officer Leon S. Kennedy to access Umbrella's underground biological warfare laboratory, where she is outed as a mercenary by scientist Annette Birkin.

She appears in the adult animated film Resident Evil: Damnation (2012), in which she poses as a Bioterrorism Security Assessment Alliance agent to infiltrate the Eastern Slav Republic and obtain a sample of the "Las Plagas" parasite used in the country's civil war.

[10][42] Set after the events of Resident Evil 2, they follow Ada's mission to retrieve Sherry Birkin's pendant with the G-virus sample from Umbrella enforcer HUNK.

[46] Writer Noboru Sugimura gave Linda's role from the discarded prototype to Ada and reinterpreted her as an enigmatic corporate spy for the final build of Resident Evil 2 to connect its story to that of the first game.

[8][17] In the 2019 remake of Resident Evil 2, more time was spent developing Ada and Leon's relationship, as the creative team felt that it had progressed too quickly in the original game.

[51] Ada's red dress from the original version of the game is initially covered by a beige trench coat in the remake, which Kadoi said was a more "realistic" and "believable" look for a spy.

[54] Producer Masachika Kawata believed that Ada deserved "to really stand out" beyond her minimal screen time in the main campaign of Resident Evil 4, and developed "Separate Ways" as a means of further exploring the character.

[59] Ada was intended to appear in Resident Evil Village (2021) as a mysterious masked figure in a plague doctor outfit who helps protagonist Ethan Winters, but she was ultimately cut from the game due to "conflicting scenarios".

[8] Chinese actress Li Bingbing played Ada in the live-action film Resident Evil: Retribution, and was dubbed by Cahill in English and Junko Minagawa in Japanese.

[64] Scholar Andrei Nae noted that Resident Evil 4 is heavily influenced by film noir, a genre in which female characters are either "submissive" – such as Ashley Graham – or femmes fatales that challenge male authority and patriarchal conventions.

Praising her as challenging of noir conventions and independence, Nae felt that Ada's identity as a Chinese-American makes her accentuated sexuality as a femme fatale conform to Orientalist clichés of East-Asian erotic femininity.

[67][68][69] Critics have argued that the in-game cinematics in Resident Evil 4 focused on Ada's slit dress – noted as unrealistic and unsuitable for a combat role – and body, holding that her appearance was intended to appeal to male audiences.

[57] Michael McWhertor of Polygon criticized the dialogue as unnatural, speculating whether Gao was given improper direction in an attempt to generate a "cool" personality that set Ada apart from Leon.