The justice system of Chittagong Hill Tracts (CHT) is characterized by the existence of a dual justice system - the formal one according to the law of the country and the customary laws of indigenous people. The broad objective of the study is to explore the formal and informal justice system of the ethnic communities in CHT in regards to assist Human Rights and Legal Aid Services (HRLS) programme of BRAC for effective extension in this area. Five ethnic groups with highest representation in the region were included in the study. They are Chakma, Marma, Tripura, Mro and Bangali. Both quantitative and qualitative data were used. For quantitative analysis, 601 samples have been observed. In contrast qualitative tools including 25 in-depth interviews, 25 case studies, 25 informal discussions and observation of four Shalish from 24 villages/paras were used. Most of the cases reconciled by the informal justice system had some advantages in terms of easy accessibility and less time and money required for making decision. Most common disputes were on fighting, stealing, land grabbing, intra- and inter-household disputes including rape and murder cases. Some inhuman punishments were executed by the customary legal system. Most people in the region preferred customary laws for having a short trial procedure, less transportation hassle and availability of witness. A number of people opined for legal aid intervention in this area. At the same time hill people are much more inclined to keep their laws stronger as a part of their identity.