Studies of the decision to intervene into ongoing civil wars should focus on those making the decision, not the conflict. We adopt such an “actor-centric” approach and discuss third-party intervention by emphasizing convergent and divergent interests and the connections between potential interveners, actual interveners, and civil war states. Our model furthermore differentiates between interventions on the side of the government and opposition and takes the sequence of interventions in the same conflict into account. The results from estimation of a mixture cure survival model support our theoretical framework and expectations. This paper thus advances our understanding not only of the effects of intervention, but also the motivation and decision to intervene.