Johannes Kana confessed to raping 17-year-old Anene Booysen before she was dumped at a building site in Bredasdorp, 80 miles east of Cape Town, in February. She had been beaten and mutilated with a knife.
Ms Booysen's murder sparked some of the biggest anti-rape campaigns in years in South Africa, with President Jacob Zuma expressing "shock and outrage" and calling for the harshest possible sentences for her attackers.
Three suspects were initially arrested but only 21-year-old Kana stood trial. He confessed to raping Booysen but denied disembowelling her.
The sentencing was met by muted clapping from Ms Booysen's relatives.