For decades now, Canada has been seen as a global exemplar of peacemaking and peacekeeping, yet the troubled relationship between its state and the Indigenous peoples within its borders does little to support this image. There is, in fact, a strong case to be made that the ongoing crisis of Indigenous–settler state relations in Canada is best understood as a protracted war; or more succinctly, as a failure to achieve peace following the initial violence of conquest and colonisation. Accordingly, it makes sense to apply just war theory — a doctrine of military ethics — to the issue. Grounded in familiar moral and legal principles, the just war tradition is fully legible to the state, yet its principles also resonate with the Indigenous philosophy of ‘decolonisation’. Because it articulates powerful theories of justice while mapping a theoretical common ground between Indigenous peoples and the settler state, just war theory emerges as a promising, and thus far neglected, framework for evolving a just peace in the wake of colonial conquest in Canada.