The study aims to identify the reasons that made Britain proclaim its protection of Zanzibar in 1890 at a time of colonial conflicts. It also aims to discover the nature of the political relationships between the British authorities and the Sultans of Zanzibar under the British protection. In addition, the study shows the effects and consequences of this protection. The researcher relied on primary sources, mainly sources from the British archive. She also used some sources and references that are relevant to the subject and used the analytical description approach to write the study. The study has an introduction, a preface and three chapters. The first chapter deals with the British protection of Zanzibar in 1890 by looking at the colonial conflict at that time until the occurrence of the British protection of Zanzibar. The second chapter discusses the nature of the political relations "between the British authorities and the Sultans of Zanzibar under the British protection, during the period of four Sultans from 1890 to1911. The third chapter focuses on the results of the British protection. They are divided into a set of political, economic, social and cultural consequences. The study concludes a number of results. The most important consequence of the British protection of the Sultanate of Zanzibar was the weakness of the Sultanate and its Sultans as a result of imposing British laws and legislation and forcing the Sultans to give up large parts of their lands. This weakness also resulted from the interference of the British authorities in the authority of the Sultans, which lead to the disintegration and weakness of the Sultanate and later lead to its downfall in 1964. In addition, the relationships between the British authorities and the Sultans were known for their ups and downs because of the different interests of the two parties, although the control was for the British. The study also demonstrates the role of Britain and its interference in the succession to empower who would best serve their interests. Besides, the study shows that since the submission of Zanzibar to the British protection from 1890 to1911, a period of the isolation of the Sultan Ali bin Hamoud, Britain tightened its grip on things gradually until it reached its absolute control over the throne to the extent that it was able to isolate the Sultan, and this is what happened to Sultan Ali bin Hamoud. The consequences and effects of the British protection of Zanzibar were numerous in all aspects: political, economic, social and cultural.