Last name Ryadh (Ryadh 
) , all around the world, is quite a rare surname. The last name Ryadh is characteristic of Algeria, where it is quite a rare surname, Tunisia, where it is a rare surname, and Iraq. Not in comparison with a country's population, the name is most common in Algeria, Iraq, and Bangladesh. More prevalently, Ryadh is the forename as well as the last name.