The 24-year-old triggered a clause in his one-year deal by making 25 appearances, keeping him at the club for another season.
Booth has agreed new terms for the next campaign and Thistle will have the option to add an extra 12 months on to his contract until May 2019.
ICYMI -CONTRACT EXTENSION: Callum Booth extends his deal until May 2018 https://t.co/iEqIoGAIq1
— PartickThistle FC (@ThistleTweet) April 6, 2016
Callum Booth is delighted with new deal https://t.co/jUiazwwARQ
— PartickThistle FC (@ThistleTweet) April 6, 2016