Family name קוסבי (Cosby 
, Kosbi 
, קוסבי 
) , around the world, is a common surname. The last name קוסבי is habitual in Guam, where it is quite a common surname, the United States, where it is quite a rare surname, and Ghana. Measured by absolute frequency, the name is most common in the United States, Ghana, and the United Kingdom. Very seldom, קוסבי is the forename as well as the last name.