Vietnamese personal names generally consist of three parts: one family name, one or more middle name(s), and one given name, used in that order. The "family name first" order follows the system of Chinese names and is common throughout the Chinese cultural sphere, but is different from Chinese, Korean, and Japanese names in the usage of "middle names", as in China and Korea it exists but is not mandatory, while in Japan it does not exist. Persons can be referred to by either the whole (full) name, the given name, or a hierarchic pronoun (which usually connotes a degree of family relationship or kinship) in normal usage.
Due to the frequency of the major family names such as Nguyễn, Trần, and Lê, a person is often referred to by their middle name along with their given name in Vietnamese media and youth culture.
The Vietnamese language is tonal, and so are Vietnamese names. Names with the same spelling (ignoring diacritics) but with different tones are different names, which can confuse non-Vietnamese people when the diacritics are dropped, in usage outside Vietnam.
Anyone applying for Vietnamese nationality must adopt a Vietnamese name.
The family name, positioned first, is passed on by the father to his children. It is estimated that there are around one hundred family names in common use, although some are far more common than others. The name Nguyễn is estimated to be used by almost 40% of the Vietnamese population. The top three names are so popular because people tended to take the family name of emperors, to show their loyalty. Over many generations, the family names became permanent.
The most common family names among the Vietnamese are the following (the Chinese characters following each name are Hán tự). Added together these 14 names account for 90% of the people.