Boyko is the name for a distinctive group of Ukrainian montagnards of the Carpathian highlands. The Boykos inhabit the western half of the Carpathians in Ukraine, and the adjacent areas of southeast Poland and northeast Slovakia.
Boyki are one of the few groups that can still be referred to as "Ruthenians" or Rusyns.
The name, "Boyko" is thought by some to originate in their patterns of speech, specifically the use of the expression, "bah!".
Most Boyki belong to the Ukrainian Greek Catholic Church, with a minority belonging to the Ukrainian Orthodox Church. The distinctive wooden church architecture of the Boyko region is a three-domed church, with the domes arranged in one line, and the middle dome slightly larger than the others.