Thai royal and noble titles signify relationship to the King. The system is somewhat complicated and usually not well understood even by most Thai people. A particular title may not be confined to just the beginning or the end of the name, but may be split across the name as will be demonstrated. Another point of note about the titles is that the King has the power to bestow any title on anybody, regardless of the rule. However, such promotion is personal and the children of the person will not normally benefit from it (see, for example, Phra Worawong Ther Phra Ong Chao]]).

The King (Sovereign)

There are two titles which can be used for a king (depending on coronation status).

Phrabat Somdej Phra Chao Yu Hua ("Crowned King")

Phrabat Somdej Phra Chao Yu Hua (พระบาทสมเด็จพระเจ้าอยู่หัว) is the normal title used by the kings of Thailand (Siam) after coronation. There are two ways that this title can be used:

• It can precede the name of the king, for example: Phrabat Somdej Phra Chao Yu Hua Bhumibol Adulyadej. This type of usage is less formal than the next possibility.
• It can be split across the name, possibly with omission or modification of the words "Phra Chao Yu Hua". For example: Phrabat Somdej Phra Paraminthara Maha Bhumibol Adulyadej, Phrabat Somdej Phra Paraminthara Maha Prajadhipok Phra Pokklao Chaoyuhua.

Somdej Phra Chao Yu Hua ("Uncrowned King")

Somdej Phra Chao Yu Hua (สมเด็จพระเจ้าอยู่หัว) is restricted to a king who has not yet gone through coronation. Once crowned, he will use the title Phrabat Somdej Phra Chao Yu Hua. This particular title normally precedes the king's name, since he has not yet been given a ceremonial name.

Sovereign's Consorts

Traditionally, titles of the royal wives depended both on their birth titles and royal favour. Only the princesses who are of high birth (Chao Fa, Phra Ong Chao, Mom Chao Ying) would be able to take up titles higher than Chao Chom . There were no clear rule about the hierarchy of the titles above Chao Chom until the time of King Mongkut; even then the titles kept changing over the successive reigns.

The rule about commoners also seems to be evolving over time; it appears that there are no more restrictions keeping a commoner from becoming queen.

Most of the titles listed here are taken from the time King [[Vajiravudh enacted the Succession Law in 1924.

The Queen

Only the holders of the titles listed here -- all containing the word "rajini" -- are the queens in the Western sense, although the concept of queen was only introduced first in the reign of King Rama V. There can be only one "rajini" at a time. The actual title depends on the status of the holder.

Somdej Phra Boromarajininat