It now appears settled that the international community may in appropriate situations and through the UN Security Council intervene militarily in sovereign States for humanitarian purposes. What do not appear settled though, are the exact circumstances when such humanitarian use of force may be justified; how such authority may be used; and whether there are any legal impediments to the use of the power. Many in fact believe that any authorisation of the use force for humanitarian purposes by the UN Security Council in reference to Chapter VII of the UN Charter would be unassailable in all circumstances or situations. They assume the Security Council to be above legal limitations on matters of use of force, even for humanitarian purposes. This article challenges this supposition. It contends that the authority of the Security Council in relation to humanitarian military intervention under the UN Charter and the Responsibility to Protect is not limited but circumscribed, not only by the UN Charter, but also by the purposes and principles of the UN and rules of International Humanitarian Law. These limitations, the article contends, far from being under-cut or undermined, have been re-enforced by the doctrine of Responsibility to Protect. The article shows that irrespective of its inclinations to the contrary, the Security Council may not legally authorise humanitarian interventions in contravention of the requisites for the use of force in international law. Using the Council’s intervention in Libya and non-intervention in Syria as case studies, the article underlines the legal limits of humanitarian military intervention and the dangers of an unbridled use by the Security Council of military force in the name of humanitarianism.