The order began in Thailand as a reform movement led by a prince who would later become King Mongkut of Siam, before also spreading to Cambodia and Burma.

Consequently, King Mongkut emphasized the use of the Pali Canon as the primary authority for monastic practices, and sought to eliminate all of the syncretic elements.

It remained a reform movement until passage of the Sangha Act of 1902, which formally recognized it as the lesser of Thailand's two Theravada denominations, the other being Maha Nikaya.

In founding the Thammayut order, Mongkut made an effort to remove all non-Buddhist, folk religious, and superstitious elements which over the years had become part of Thai Buddhism.

[5] According to anthropologist Jim Taylor, Vajirañāṇavarorasa's autobiography tells how "Thap had differences with the somewhat more "worldly" bhikkhus at Wat Bowornniwet, which led to dissension and the movement's eventual division into four primary competing factions (monastic lines or "stems")."

In the mid-19th century these branches became so estranged that each one developed its own style of chanting, interpretation, and translation of Pali texts, and differed on issues related to the monastic code.

[7][6] Thanissaro, a Thai-ordained forest bhikkhu, notes though that in the early-20th century, Ajahn Mun's kammaṭṭhāna lineage formed a distinct camp within the Thammayut order which was at odds with Vajirañāṇavarorasa's reforms.

[9][10] Having been started by a Thai prince, the order has always had close ties to the monarchy and has historically played a key role in ensuring public support for the palace.

Journalist Paul Handley writes that:Although the doctrinal differences between the schools had become less significant, putting Thammayut [sic] on top ensured that the sangha remained closely allied with the palace.

In reality, the military junta persecuted Phra Phimontham for his political views and disseminated the false charges in the media in order to arrest him and limit his influence, and to consolidate its power over the Sangha.

[19][20][21] On 7 February 2017, Prime Minister Prayut Chan-o-cha confirmed the appointment of Somdet Phra Maha Muniwong as the 20th Supreme Patriarch of Thailand in a televised address.

Taylor argues that this was done in order to ensure that the next supreme patriarch is also from the Dhammayuttika Nikaya, pointing to the junta's previous interference with the position in 2017 and that the suspects were all high-ranking non-royalist bhikkhus.

[24] In fact, in July 2018, the junta passed a law giving the Thai King the ability to select members of the Sangha Supreme Council instead of the monks.

[29] In 1991, King Norodom Sihanouk returned from exile and appointed the first new Dhammayuttika Sangharaja in ten years, effectively ending the policy of official unification.

[30] The Dhammayutti Mahayin Gaing (Burmese: ဓမ္မယုတ္တိနိကာယမဟာရင်ဂိုဏ်း; from Pali: gaṇa "group, association") has its origins as "a late nineteenth-century Mon reform tradition [that] traces its lineage to the Thai Thammayut (sic) order.