Karzin (Persian: كارزين) is a city in the Central District of Qir and Karzin County, Fars province, Iran, serving as the administrative center for Fathabad Rural District.

At the 2006 census, its population was 7,953 in 1,651 households. The following census in 2011 counted 8,446 people in 2,153 households. The latest census in 2016 showed a population of 8,841 people in 2,520 households.