This paper considers the history of the Ibadi Muslim communities on the island of Djerba in Tunisia over a period of several centuries (with particular emphasis on the 10th-14th centuries) through the lens of ecological history. The basic argument is that the history of Djerba’s Ibadi communities are inextricably tied to the geography of the island. It presents a long-term, thematic historical description of the interaction between the geography and environment of the island and its Ibadi inhabitants. In doing so, it draws connections between certain elements of Ibadi socio-political organization and environmental and geographical actors throughout the early centuries of Islam in Djerba. The foci of inquiry include water resources, climatic factors, geographic insularity, maritime resources and technology, agricultural development and the distribution of surviving religious structures on the island. Building upon original and previous research in the fields of archaeology, history and geography, the paper attempts to synthesize the methodologies of these fields in order to work toward an historical ecology of Ibadism in Djerba.