Thailand is a Buddhist country where Buddha images are held secret. Sacrilegious acts are punishable by imprisonment even if committed by foreign visitors.

Thai people hold their King and Queen and the Royal Family in great reverence, and so won't tolerate foreigners showing disrespect to them.

Generally Thai women are conservative. So don't touch them without their consent.

Dress properly when entering a Buddhist temple. Mini-skirts and shorts are not allowed. Take your shoes off before going inside the hall of worship. Ladies must not on any account touch a Buddhist monk, give things direct to him or receive things direct from him.

Intimacies between man and woman should not be shown in public. Sunbathing in the nude is prohibited.

Traditionally, Thai greet each other with a wai (by pressing the palms together at the chest). If someone wais you, you should way back (except wai-ed by a child).

Call Thai their first names; use title "Khun" for adults.

Thai people smile to express gladness and happiness, to thank for small services, to return the wai (a way of greeting) of children and inferior persons, and even to excuse small inconveniences.

Don't touch a persons head, do not ruffle the hair.  The had is the noblest part of the body. A sincere apology should be offered immediately if you touch someone's head unintentionally.

Avoid placing your feet on the table while sitting. Never use your foot to point things out or to touch any part of the of the body of anyone, which is considered rude.

Entering a Thai home, you're expected to remove your shoes.