The Charter of the United Nations clearly states the principle of prohibiting the use or threat of force in international relations, which means that one-sided humanitarian interventions are unlawful, and yet there is a side of jurists and researchers trying to circumvent this principle to justify the legitimacy of one-sided humanitarian interventions. They offer several arguments and justifications, such as that one-sided humanitarian interventions do not contradict the proper interpretation of the United Nations Charter, and that there is an emerging rule in customary international law that permits such interventions, and that endorsement of the principle of the responsibility to protect includes authorization to undertake one-sided humanitarian intervention. This article seeks to emphasize the illegality of one-sided humanitarian interventions in international law, and this conclusion is reached after careful analysis and refutation of the previous arguments and allegations made by some to legitimize these interventions.