Harsin (Persian: هرسين) is a city in the Central District of Harsin County, Kermanshah province, Iran, serving as capital of both the county and the district. The city is populated by different Kurdish tribes including the Osmanvand and the Jalalvand who speak Laki. Harsin was founded in 550 BC.

At the 2006 National Census, its population was 51,562 in 12,001 households. The following census in 2011 counted 49,967 people in 13,700 households. The latest census in 2016 showed a population of 44,146 people in 12,814 households.