Qatar Aghaj (Persian: قطاراغاج, also Romanized as Qaţār Āghāj; also known as Ghatar Aghaj, Qaţār Āqāj, and Qatrākhāj) is a village in Shirin Su Rural District, Shirin Su District, Kabudarahang County, Hamadan Province, Iran. At the 2006 census, its population was 223, in 48 families.