This paper details the data collection process, dataset, and reuse potential of the Balkan Peace Index, a model designed to evaluate the levels of peacefulness in the Western Balkans. Data was gathered in phases initially, a team of local experts conducted on-ground data collection, interviews, and focus groups, as well as using external international databases describing different notions of peace. This data was then processed and classified on a predefined scale by another team of experts using the Decision EXpert model. The BPI model incorporates both quantitative and qualitative data, reflecting the local context. The comprehensive dataset is stored in the Mendeley Data repository and offers significant reuse potential for further research, policy-making, and sensitivity analysis. This open-access resource aims to provide actionable insights for improving peace levels and preventing potential deterioration in the region.