Colonial British India witnessed a large increase in the formation of socio-religious reform movements during the nineteenth and twentieth centuries. The major religious groups in British India sought to address the criticisms of Christian missionaries, enact responses to changing social and economic conditions under British imperialism, and attempt to resolve problems in their communities. This article examines the work of Daud Shah, an advocate for socio-religious reforms among Tamil-speaking Muslims in the Madras Presidency and the Bay of Bengal littoral. Existing research on Shah has examined his work within the context of social and political developments within the colonial Madras Presidency. This article argues that a proper assessment of Shah's contribution to socio-religious reform can only be made by including the transnational aspects of his reform efforts, including sources of his religious knowledge and the impact of his actions on the diasporic community of Tamil Muslims in the Indian Ocean.