Clarissa Explains It All is an American teen sitcom created by Mitchell Kriegman for Nickelodeon. In the series, Clarissa Darling (Melissa Joan Hart) is a teenager who addresses the audience directly to explain the things that are happening in her life, dealing with typical adolescent concerns such as school, boys, pimples, wearing her first training bra, and an annoying younger brother.

A total of 65 episodes were produced and aired from March 23, 1991, to October 1, 1994, with repeats airing until August 19, 2001. From August 1992 onwards, the series headlined the popular SNICK (Saturday Night Nickelodeon) lineup. Reruns of the show have appeared intermittently on TeenNick's channel block The '90s Are All That, eventually NickRewind, from 2011 to 2020.

A pilot for a spin-off series was filmed titled "Clarissa Now". It featured Clarissa as an intern at a newspaper in New York City. The pilot was not picked up, and aired once as a special on Nickelodeon.

In 2015, Kriegman released a novel, Things I Can't Explain, which serves as a sequel to the series. In the novel, Clarissa is now in her late 20s and trying to navigate life as an adult. In March 2018, it was reported that a sequel to the series was in development at Nickelodeon, with Clarissa now as a mother. In March 2022, Hart revealed the reboot was not moving forward at Nickelodeon.