Fi is a Turkish psychological thriller television series originally streamed online by puhutv. It is an adaptation of Azra Kohen's novels Fi, Çi, and Pi. The first season of it consists of 12 episodes which aired from 31 March 2017 to 16 June 2017. The second season started in October 2017.
Within 50 hours of the first three episodes being aired, it reached 3.5 million viewers. The first 9 episodes reached 50 million viewers.