Animal domestication is a profound change for human societies, economies, and worldviews. The shifting definitions of animal domestication reflect its varying and process-like nature. Reindeer is one of the species whose domestication is not easily pinned down using standard definitions and research methodologies of animal domestication. In recent years, advances in archaeological methodology and the conceptual understanding of animal domestication have opened new avenues for research on this topic. This review summarizes recent research on the archaeology of reindeer domestication among the Indigenous Sámi of northern Fennoscandia. It compiles a chronological framework of reindeer domestication with an emphasis on the development of reindeer-herding practices and human–reindeer relationships. I argue that while a major transition to reindeer herding occurred among the Sámi from the 15th century onward, small-scale reindeer herding characterized by interspecies sociality, cooperation, and care developed earlier during the Late Iron Age, with regional variations in the timing and details of the events. By focusing on reindeer-herding practices and the human–reindeer relationships embedded in them, I also argue that reindeer domestication, and animal domestication in general, is a relationship constructed and constantly renegotiated in everyday interactions with the animals.