Třinec (Czech pronunciation: [ˈtr̝̊ɪnɛts]; Polish: Trzyniec , German: Trzynietz) is a town in Frýdek-Místek District, Moravian-Silesian Region of the Czech Republic. It lies on the Olza River, in the historical region of Cieszyn Silesia. The town has 37,405 inhabitants as of 2009, in 2001 17.7% of the population were Poles.