Globally the ‘peace process’ has emerged as the prime device whereby organised insurrectionary movements are facilitated to shift to peaceful contention, yet such processes remain radically under-researched in social movement theory. Drawing on original qualitative data from insurrectionary social movement families in Northern Ireland, and on comparative data from South Africa and the Occupied Palestinian Territories, a model is constructed of the shift to less violent politics. Peace processes involving social movements formerly linked to violence invariably require vast frame-shift in participating organisations (frame-transformation, frame-bridging, and radically re-engineered diagnostic, prognostic and motivational framing). The data support the hypothesis that frame-shifts are intimately linked to changes in mobilising and political opportunity structures. As regards the former, framing appears geared to rationalise shift from military to political structures. As regards the latter, the shifts support the hypothesis of two-way interaction between framing and opening of political opportunity structures. The processes should not be considered solely on a national basis. There is ample evidence of cross-national frame diffusion affecting formerly violent social movement organisations.