: The paper examines the role of the United Nations as a guarantor of global peace and security, and the changing landscape of conflict in Africa in the 21st century. Africa as a continent, since the beginning of the 21st century has been plagued by a complex and diverse plethora of socio-economic, political and environmental challenges that constitute a clog in the wheel of economic development and political stability. From the findings, the study reveals that of the fourteen ongoing UN peacekeeping operations globally, seven are presently ongoing in Africa. The study further reveals that most of these conflicts are resource-based conflict arising over economic alienation, unequal distribution of wealth, competition for power, and climate change arising from resource depletion and population explosion. The study observes that some of the challenges facing the United Nations Peacekeeping operations in ongoing conflicts in Africa are multidimensional and calls for swift ranging reforms. Such challenges include the role of the host state, terrorism and counterterrorism, sexual abuse, and human rights violations by peacekeeping troops, inability of troops in protecting civilian population from genocide and state sponsored violence. The study also reveals that the multi-polarity of actors who recently intervened in African conflicts such as Russia, Iran, Saudi Arabia, UAE, Turkey etc. do not have any strategic interest but rather a destabilizing role should be of serious concern to the stability of the continent. This is because the prospect of resolving such conflict through diplomacy and multilateral peacekeeping operations using the United Nations, regional bodies such as the African Union, ECOWAS, AGAD, SADDC etc. becomes a herculean task. The study therefore, recommends that the UN rules of engagement in conflict prevention and management be reformed, so as to ensure that peacekeeping troops who are found guilty of committing heinous crimes such as sexual assault, rape, indiscipline, murder, should be prosecuted by the host state where the crime was committed.