This paper integrates peacebuilding components into sustainability impact assessment (SIA) for application in geographies vulnerable to, recovering from, or experiencing conflict. Based on the understanding that peace is a crucial pre-requisite for sustainable development and vice versa, it argues that integrating peacebuilding into SIA will enhance the development potential; particularly in conflict-affected countries. So far, SIA does not address this nexus of development and peace. Comprehensive SIA prior to implementation (i.e. ex-ante) facilitates reflections on outcomes (positive and negative), helping to design context-specific best-fit interventions. The objective of this study is to develop a set of peacebuilding indicators for future impact assessments. The study finds that existing SIA tools address many aspects, particularly economic and environmental impacts, but, although crucial to enhance societal relations and peace(building), these neglect societal aspects relating to social cohesion, agency, and transformation capacity. Thus, 17 indicators for assessing peacebuilding potential are proposed for integration in SIA in conflict-affected areas. The indicators are grouped into four components aligning with the key areas identified as missing in existing SIA frameworks but also crucial for positive peace: social cohesion, agency, negotiation capacities, and compensations.