Family name Гайка (Gaika 
, Гайка 
, Gayka ) , all around the world, is a rare surname. The cognomen Гайка is characteristic of South Africa, where it is a rare surname, Bulgaria, and Ukraine. Not in comparison with a country's population, it most frequently occurs in South Africa, Ukraine, and Russia. Very seldom, Гайка is the forename as well as the last name.