The 22-year-old former Dunstable Town defender joined in January 2020 under previous boss Graeme Jones, when he was signed from National League outfit Hartlepool following an impressive 18 months at Victoria Park.
He made his Town debut as a late substitute in the crucial 1-0 win at Hull City as Luton stayed up, while the following term he played twice, including starting the Carabao Cup third round tie with Manchester United.
Kioso then went on loan to Bolton Wanderers for the first half of the season, finishing the campaign at Northampton Town.
Last year, the full back started in the first team at Kenilworth Road with four outings, but following the 5-0 defeat to Birmingham, he went to MK Dons, the club he started his career at,
His four month stay was ended when recalled by the Hatters as he went on to play 15 times in all competitions, with six starts, as Town reached the Championship play-offs, his last appearance coming in the 7-0 defeat to Fulham.
Kioso, who made 22 appearances in total for Luton, was now signed a three year deal at the AESSEAL New York Stadium and will join his new team-mates in training on Friday.
A statement on the Hatters’ official website said: “We would like to thank Peter for his contribution over the last two-and-a-half years and wish him well for the future.”