Surname เรืองใจ (Happy 
, เรืองใจ 
, Ruangjai ) , all around the world, is a common family name. The surname เรืองใจ is characteristic of Sub-Saharan Africa, particularly Nigeria, where it is quite a common surname, Namibia, where it is quite a rare surname, and Eswatini. Measured by absolute frequency, it is the most numerous in Nigeria, Bangladesh, and Indonesia. More prevalently, เรืองใจ is the forename as well as the last name.