This book explores the ethnogenesis, their integration in host societies and their bonding in the Indian diaspora of Girmitiyas— a population of over 1.3 million British-Indian indentured labourers recruited in the nineteenth and twentieth centuries to work in plantation colonies across Asia, Africa and the Caribbean. Focusing on Girmitiya communities in Suriname, Guyana, Mauritius, and Fiji, it examines both the similarities and divergences in their ethnic formation, integration into host societies, and diasporic bonding. Theoretically, It contributes to the underexplored but vital themes of ethnogenesis, integration, and diaspora connections, highlighting variations within and across communities. It traces how ethnic identities emerged in different contexts and how these groups negotiated ties with both their adopted homelands and the wider Indian diaspora. Drawing from comparative insights, it provides a unique framework for analyzing community evolution across geographic and cultural boundaries. Empirically, the book offers detailed historical accounts of the Girmitiyas in four societies, marking a significant departure from the largely single-country focus of existing literature. By presenting a comparative and transnational perspective, it moves beyond plantation narratives to situate Girmitiya communities within broader social, cultural, and political histories. This volume will be valuable intervention in the social sciences and the humanities, especially in ethnic studies, peasant studies, diaspora studies, and the analysis of plural societies.