In all the world, Issaac (Issaac 
) is a rare boy's first name. The first name Issaac is characteristic of the Dominican Republic, where it is a rare masculine name, the Democratic Republic of the Congo, and Tanzania, where it is a very rare masculine name. Not in comparison with a country's population, the name is most common in the Democratic Republic of the Congo, Nigeria, and the United States. Much less frequently, Issaac is the last name as well as the forename.