William Michael Zabka (; born October 20, 1965) is an American actor. He portrayed Johnny Lawrence in The Karate Kid (1984), The Karate Kid Part II (1986) and the TV series Cobra Kai (2018–2025).

Zabka's career took off with The Karate Kid, despite having no prior karate training. During the 1980s, he appeared in the films Just One of the Guys (1985), Back to School (1986), and the television series The Equalizer (1986–1989). In the 1990s and 2000s, Zabka focused on independent films and filmmaking. In 2004, he was nominated for an Academy Award for co-writing and producing the short film Most. Zabka continued directing, including music videos for Rascal Flatts. In 2018, he reprised his role as Johnny Lawrence in the YouTube Red and Netflix series Cobra Kai, which he co-executive produces with Ralph Macchio. The series, set 33 years after the original film, explores the re-opening of the Cobra Kai dojo and the rekindling of the rivalry between Johnny Lawrence and Daniel LaRusso.