The mahori (Thai: มโหรี, pronounced [mahǒːriː]) is a form of Thai classical ensemble traditionally played in the royal courts for the purpose of secular entertainment. It is also popular in Cambodia It combines the xylophones and gong circles (but not the pi, or oboe) of the piphat with the strings of the khruang sai ensemble. Originally, the term referred only to a string ensemble, although today it includes both string and percussion. There are three broad types of Mahori: Mahori Khryang Lek, Mahori Khyrang Khu, and Mahori Khyrang Yai, each differentiated by the types of instruments utilized.
Initially, only men were permitted to play mahori; however, as its popularity grew, women from royal backgrounds began to play as well. In the Ayuthaya period, women were not permitted to act onstage outside royal service, and women were trained only to play in the mahori. However, King Rama IV removed this restriction and allowed women to act onstage, which caused women's mahori to decline as women increasingly chose to act instead.
While Thai classical music was somewhat discouraged as being outmoded and backward-looking during Thailand's aggressively nationalistic modernization policies of the mid-twentieth century, the classical arts have benefited recently from increased governmental sponsorship and funding as well as popular interest as expressed in such films as Homrong: The Overture (2003), a popular fictionalized biography of a famous early 20th century ranat ek player and composer Luang Pradit Phairao.