The DHARMA Transliteration Guide describes a comprehensive system of Romanised transliteration for South and Southeast Asian languages written in historic regional scripts. The languages to which it applies include, but are not limited to, Balinese, Cham, Javanese, Kannada, Khmer, Malay, Prakrit, Sanskrit, Sundanese, Tamil and Telugu. The foundation of the scheme outlined here is the ISO-15919 transliteration standard, which, however, covers a somewhat smaller gamut of languages. Moreover, certain modifications and extensions of the standard provide transliteration solutions for orthographic specificities that were deemed irrelevant to textual studies by the creators of the ISO standard, but which may be of considerable research interest in some niches, namely in the preparation of epigraphic editions and diplomatic editions of manuscripts. This document contains guidelines for work in the ERC project DHARMA, but it is hoped that the practice recommended here will be a major step in establishing wider new standards in the fields of South and Southeast Asian studies.