Jasień [ˈjaɕɛɲ] (German: Gassen; Lower Sorbian: Gase gase; Upper Sorbian: Gózdne) is a town in western Poland, in Lubusz Voivodeship, in Żary County.

During World War II Jasień was the location of the Nazi German slave labour camp AL Gassen, one of nearly one hundred subcamps of the Gross-Rosen concentration camp.

[2] Its prisoners, mostly Poles, but also Soviet prisoners of war, Czechs, Croats, Frenchmen, Romanians, Italians, Hungarians, Greeks, Serbs, Lithuanians, were making warplane parts for Focke-Wulf AG.

[2][3] The camp, with around 700 acutely malnourished prisoners, operated from August 1944 until 13 February 1945, when the remaining workforce was sent on a death march to the Buchenwald concentration camp ahead of the Soviet advance.

[2][4] The local football club is Stal Jasień.