Customary law is unwritten traditional law which is usually prevalent in tribal society has great impact on live of the Tagin in the regard to matters such as marriage, inheritance, traditional authority, guardianship, and so forth. By focusing on this particular study was carried out in Tagin community of Arunachal Pradesh. This present study is attempted to examine the customary law and its impact on gender inequality among Tagin is considered for the study which is more descriptive and qualitative in nature. Study reveals that Society set norms and values are patriarchal in nature, this patriarchal structure sidelines woman by male domination in almost everything whereas men are considered as superior to women in given society. Customary Norms and values of this particular Community have been beautifully structured the role of genders which would bring social stability in society wherein women are assigned with easy task and men are hard on the basis of sex. In this community women are treated as inferior to men in any social setting.