This chapter demonstrates how the norm regimes of counter-terrorism and the responsibility to protect share a basis in international law and the obligations of the state. However, depending on how these norm regimes are interpreted and implemented, they may either contradict or reinforce each other. This will be demonstrated through two case studies, Sri Lanka’s use of counter-terrorism during the civil war against the Tamil Tigers which amounted to the commission of war crimes and the application of R2P in the conflict against the Islamic State which supported interventions to protect civilians. While both norm regimes remain deeply contested, their simultaneous evolution continues to place them on a trajectory to make them increasingly more collaborative and complimentary. The positive congruences between the two regimes represent a potentially more effective way of addressing both R2P and terrorism crimes. What remains to be seen is how that relationship will play out and whether or not the protection of civilians is given the same effort and attention as initiatives to stop terrorism.