What responsibilities does planning have when the sites it regulates are also places of historical trauma? Across Ireland, former sites of institutional confinement and abuse, including Mother and Baby Homes, Industrial Schools and Magdalene Laundries, are increasingly subject to redevelopment, regeneration and adaptive reuse. While significant attention has been paid to questions of historical accountability, memorialisation and survivor recognition, the role of planning in shaping the future of these sites remains under-examined. This research argues that planning is not a neutral regulatory process but an active participant in determining how difficult histories are remembered, contested and transformed. The research presents a conceptual framework organised around three interconnected themes: system, conflict and possibility. The first examines the planning system, including policy, governance and legislative frameworks, and their capacity to respond to sites associated with historical harm. The second explores conflicts that emerge between development pressures, heritage considerations, survivor perspectives and public memory. The third considers ethical and inclusive planning approaches that support recognition, participation and restorative outcomes. Situated within debates on planning ethics, collective memory and transitional justice, the research seeks to expand understandings of planning's role in post-institutional landscapes. In doing so, it contributes to emerging discussions on how planning theory and practice can engage with contested heritage and difficult pasts. The research argues that former sites of institutional abuse present an important opportunity to reconsider the responsibilities of planning in contexts where questions of memory, justice and redevelopment intersect.