Thai names follow the Western European pattern in which the family name follows a first or given name. In this they differ from the family-name-first pattern of the East Asian tradition.
Thai names, both given name and family, are often long and there are a great many of them. The diversity of family names is because they are required to be unique to a family, and they are a recent introduction. Further, Thai people change their family names relatively frequently (this practice being virtually unknown in many other countries outside of marriage and Fortune-telling traditions).