Throughout the world, Рейдар (Reidar 
, Рейдар 
) is a rare male given name. The forename Рейдар is characteristic of Northern Europe, particularly Norway, where it is quite a rare boy's name, Sweden, where it is a rare male name, and Denmark. Measured by absolute frequency, it is commonest in Norway, Sweden, and the United States. Very seldom, Рейдар is the last name as well as the forename.