Intentional dental modification, in the form of ablation and filing, is reported for the first time from Cambodia in two late prehistoric sites (Phum Snay and Phum Sophy, c. 2500 to 1500 bp). Bioarchaeological research is relatively new for this region, and this study significantly adds to our reconstruction of past behaviours in mainland Southeast Asia. The skeletal samples combine both excavated material and large looted collections in the form of ossuaries. People from Phum Sophy and Phum Snay had similar rates of anterior maxillary dental ablation, 60 and 47%, respectively, and 21.4 and 7.7%, respectively, in the mandible. Patterns of ablation most commonly involve the removal of the maxillary lateral incisors. Intentional filing was less common than ablation but affected Phum Snay and Phum Sophy individuals to a similar level (47%). Filing was also restricted to the anterior dentition, and a range of patterns were evident, many involving filing of the mesial and distal aspects of the crown of the upper and lower incisors and canines to give a pointed appearance. Patterns of ablation or filing were not strongly associated with a particular sex or age group. However, a limited number of ablation and filing patterns were exclusive to each site. The significance of this practice in relation to rites of passage, status, community and family relationships, and trauma is discussed. It is also shown that the modifications show distinct differences in prevalence and pattern, particularly that of filing, to nearby temporal neighbours in southern Cambodia and northeast Thailand, suggesting a unique cultural behaviour for this region.