This thesis explores the Large Group Intervention approach (LGI) regarding its relevance and applicability in the field of peace mediation. LGI originated from organizational development with a focus on managing change in complex systems. LGI is a common-ground oriented process that allows involving large groups that reflect the composition of the whole system affected by certain issues. The participatory approach claims to foster self-organization while respecting leadership authority. The thesis thus studies an under-researched intersection of two distinct and established fields of work. The findings indicate the relevance of the LGI approach, offering insights for dialogue and mediation peace practice for different phases and tracks in peace processes.