Across the world, Йоо (Joo 
, Yoo , Ioo 
) is a common gender-neutral forename. The forename Йоо is habitual in Portugal, where it is quite a common masculine name, Egypt, where it is quite a rare unisex name, and South Korea, where it is quite a rare feminine name. Not in comparison with a country's population, it is the most numerous in Egypt, Portugal, and China. Likewise, Йоо is the last name as well as the forename.