Košařiska (Polish: Koszarzyskaⓘ) is a municipality and village in Frýdek-Místek District in the Moravian-Silesian Region of the Czech Republic.

It lies in the historical region of Cieszyn Silesia, in the Moravian-Silesian Beskids mountain range.

The highest point is the Ostrý mountain at 1,044 m (3,425 ft) above sea level, located on the northern municipal border.

According to the censuses conducted in 1880–1910 the population of the municipality dropped from 480 in 1880 to 471 in 1910 with a majority being native Polish-speakers (between 96.8% and 100%) accompanied by German-speaking people (at most 15 or 3.2% in 1880).

Following the Munich Agreement, in October 1938 together with the Trans-Olza region it was annexed by Poland, administratively adjoined to Cieszyn County of Silesian Voivodeship.