Tsui Man-kong (Chinese: 徐文光, Vietnamese: Từ Văn Quang), known professionally as Tsui Hark (Chinese: 徐克, Vietnamese: Từ Khắc, born 15 February 1951), is a Hong Kong filmmaker. A major figure in the Golden Age of Hong Kong cinema, Tsui gained critical and commercial success with films such as Zu Warriors from the Magic Mountain (1983), the Once Upon a Time in China film series (1991–1997), Green Snake (1993), The Lovers (1994), and The Blade (1995). His credits as a writer and producer include A Better Tomorrow (1986), A Chinese Ghost Story (1987), The Killer (1989), Swordsman II (1992), New Dragon Gate Inn (1992), The Wicked City (1992), Iron Monkey (1993), and Black Mask (1996).

Amid the Hong Kong handover, Tsui briefly pursued a career in the United States, directing the Jean-Claude Van Damme-led films Double Team (1997) and Knock Off (1998), before returning to Hong Kong. Since the early 2000s, he has shifted to Mainland-Hong Kong co-productions and found success with blockbusters such as the Detective Dee film series, Flying Swords of Dragon Gate (2011), The Taking of Tiger Mountain (2014), and The Battle at Lake Changjin (2021).

Tsui was born in Saigon, Vietnam, to a large Chinese (Hoa) family with sixteen siblings. He was moved by his father to Guangzhou, China as a child, and grew up there until immigrating to Hong Kong when he turned 14. Tsui showed an early interest in show business and films; when he was 10, he and some friends rented an 8mm camera to film a magic show they put on at school. He also drew comic books, an interest that would influence his cinematic style.

Tsui started his secondary education in Hong Kong in 1966. He proceeded to study film in Texas, first at Southern Methodist University and then at the University of Texas at Austin, graduating in 1975. He claims to have told his parents he wanted to follow in his father's footsteps as a pharmacist, and that it was here he changed his given name to Hark ("overcoming").

After graduation, Tsui moved to New York City, where he worked on From Spikes to Spindles (1976), a noted documentary film by Christine Choy on the history of the city's Chinatown. He also worked as an editor for a Chinese newspaper, developed a community theatre group and worked in a Chinese cable TV station. He returned to Hong Kong in 1977.

Tsui returned to Hong Kong in 1977 and worked for TVB, the dominant local television station, then moved to its rival, CTV, lured by its general manager Selina Chow. Viewed as having an eye for talent (numerous future New Wave directors got their first directing gigs under Chow) she put Tsui in charge of the martial arts drama, The Gold Dagger Romance, which marked him as a talent to watch.

Producer Ng See-yuen saw Gold Dagger Romance and hired Tsui to direct his first feature, The Butterfly Murders (1979), a technically challenging blend of wuxia, murder mystery and science fiction / fantasy elements. His second film, We're Going to Eat You (1980), was a blend of cannibal horror, black comedy and martial arts. He was quickly typed as a member of Hong Kong's "New Wave" of directors.

Tsui's third film, Dangerous Encounters of the First Kind (1980), was a nihilistic thriller about delinquent youths on a bombing spree. Heavily censored by the British colonial government, it was released in 1981 in a drastically altered version titled Dangerous Encounter – 1st Kind (or alternatively, Don't Play with Fire). The movie out-grossed Tsui's previous two films, however and made him a darling of film critics with writers describing it as "one of those very rare films in the history of Hong Kong cinema that brims with accusation and subversion" and saying that it described "man as trapped animals — this is the popular theme of the New Wave and the one enduring image in their narratives."