African history in the first half of the 20th century is largely a history of colonialism and decolonisation. In this chapter, I will consider the national movements that led the struggle against colonialism in Africa. The chapter is divided into five sections. After the introduction, there is a brief discussion of the concept of social movements and of nationalism, after which the third section examines the key factors that led to the growth of national movements across Africa. These factors include oppressive colonial policies and harsh economic conditions. The growth of towns and cities, and the rise of new religious movements also intensified these national movements, as did international developments like the two World Wars, Pan-Africanism, and the formation of the United Nations. I also focus on the roles that women played in these national movements. The fourth section examines the roles that the national movements played in the decolonisation process. The chapter concludes with an examination of nationalism in postcolonial Africa.