Prisoner (known in the UK and the US as Prisoner: Cell Block H) is an Australian television soap opera, which broadcast on Network Ten (formerly the 0-10 Network) from February 27 (Melbourne) February 26 (Sydney) 1979 to December 1986 (Melbourne), though the series finale would not screen until September 1987 in Sydney, where it aired as a three-hour film that was split into three one-hour episodes at the much-later time-slot of 10:30 p.m., running eight seasons and 692 episodes.

Prisoner was the first Australian series to feature a primarily female-dominated cast and carried the slogan "If you think prison is hell for a man, imagine what it would be like for a woman!"The series, produced by the Grundy Organisation, was conceived by Reg Watson and filmed at the then Network Ten Melbourne Studios at Nunawading and on location.

The series garnered an international cult following, and it was one of Australia's most successful media exports, and was exported to 80 countries, performing particularly well in the United States and Canada (billed as Prisoner: Cell Block H and Caged Women, respectively). It also built a large audience in the United Kingdom and other European countries, especially Sweden.

Sammy Davis Jr. was a major fan and visited the set, and wanted to appear in a role, but had other engagements at the time.The cult status of the series has seen many adaptations, including the modern 21st century re-imaging series Wentworth on Foxtel.