Thai surnames are barely a century old
Updated 2026-08-11
Here is the part that surprises people: the Thai surname is a modern invention. Until it arrived, people in Siam carried a given name and nothing more. To pin down who you meant, you referred to someone's parents, or to the place they lived.
That means Thailand's surname system is only a little over a century old — far younger than the nickname tradition, which reaches back to the Sukhothai era, centuries earlier.
The Surname Act
The turning point was the Surname Act (พระราชบัญญัติขนานนามสกุล), promulgated by King Vajiravudh (Rama VI) on 22 March 2455 BE and in force from 1 July 2456 BE (1913). From then on, having a surname was a legal requirement.
King Vajiravudh personally granted a total of 6,464 surnames. The very first Thai surname was Sukhum (สุขุม).
Why Thai surnames are long — and unique
The reason Thai surnames are conspicuously longer than those of other countries is that the law requires a new surname not to duplicate any existing one. When a name must be unique to a single family, it has to be built from longer, more specific elements.
Under the Person Name Act BE 2505 (1962), a new surname must be no longer than ten Thai consonants (excluding vowel symbols and diacritics), must not duplicate an already-registered surname, must not carry a vulgar meaning, and must not resemble the name of the king or queen.
The data bears this out. One survey covering 45,665 names found that 81% of the family names in it belonged to exactly one family — a world away from countries where a few surnames are shared by millions.
Surnames in Thai-Chinese families
Surnames in Thai-Chinese families are mostly derived from the original Chinese surname, usually keeping a hint of it in the new Thai name. A well-known example is Shinawatra, adopted in 1938, where 'Shin' derives from the Chinese surname 丘.
Women's surnames after marriage
The rules for women have been rewritten several times. Under the 1913 Act a married woman could decide for herself, taking her husband's name or staying with her own. The Personal Name Act of 1941 removed that choice and made the husband's surname compulsory.
The 1962 revision softened it: a divorcee could go back to her own surname, and a widow could choose between keeping her husband's and reclaiming hers. The Personal Name Act of 2002 finally gave a married woman the right to choose her maiden name or her spouse's — selecting one at the time of marriage registration — and allowed a couple to use different surnames.
Frequently asked questions
- When did Thai people start having surnames?
- From 1 July 2456 BE (1913), when the Surname Act came into force. Before that, Thais carried only a given name; you identified someone through their parents or their home town.
- Can two Thai families share a surname?
- A newly registered surname must not duplicate an existing one under the Person Name Act BE 2505, which is why Thai surnames are so distinctive — 81% were unique in one sample.
- How long can a Thai surname be?
- No more than ten Thai consonants, excluding vowel symbols and diacritics — royally granted names being the exception.
- Do surnames follow the Tāksā rules?
- By tradition Thaksa-Pakorn is applied to the given name, since a surname is inherited by the whole family and much harder to change. The auspicious-letter choice therefore focuses on each person's own first name.