This chapter argues that the successful entrenchment and propagation of Islam and Muslim practices in a colony proclaimed as Christian in its root and orientation was a multiethnic effort, contrary to the assertion of the dominant literature. The collective efforts of Muslim clerics, agents, and missionary activists from diverse ethnic communities contributed greatly to the acceptance of Islam as a major force in the colony by “Christian Creoles” and the colonial administration. The prevailing Temne Islamic Community (TIC) and the numerous Islamic institutions it established undergirded this multiethnic enterprise. On this basis, this chapter shows the growing influence of the Temne community in the social formation of the colony. It also argues that the Temne Islamic Community, including those who identified themselves as Temne Islamic missionaries and elites, played a much bigger role in the propagation, popularization and/or Sierra Leonization of Islam than acknowledged in the historical literature. Like the TTA and cultural associations, Islam also became a symbol of pan-Temne unity.