Violence against women is widespread in Papua New Guinea (PNG), particularly in the Highlands region, and has been demonstrated to be reinforced by customs such as polygyny. While resource extraction projects provide an important opportunity to achieve national and regional development, new wealth flows introduced by resource extraction have the potential to change customs that affect women and impact on violence against women in project affected areas. The Hela Province of PNG is in the construction phase of a multi-billion dollar Liquefied Natural Gas Project (LNGP), an extraction project of unprecedented scale in PNG. A significant amount of wealth is being distributed into the Hela Province by the LNGP. Using data from ten in-depth interviews and 11 focus group interviews with 71 female and three male participants from Huli communities living in the Hela Province, this study finds that wealth introduced into the Hela Province from the LNGP is affecting the custom of polygyny as well as having impacts on sexual relationships and family life. In addition, violence against women and family neglect are identified as some of the follow-on effects of the changes to polygyny and sexual relationships. The findings therefore suggest that wealth from the LNGP is exacerbating pre-existing social problems in the Hela Province. The study concludes by identifying three policy recommendations and delineating some critical avenues for future research.