Unlike other social sciences, the archaeological discipline has been lacking a theoretical framework to discuss the mechanism of migration. Traditionally, patterns of population movements were denoted from material culture and interpreted within the context of ethnicity and the diffusion of ideas without considering underlying processes and incentives, despite active consideration of these issues by geographers and sociologists. It was not until the 1990s that a more integrated archaeological discussion on the various stimuli, influences and mechanisms of why people choose to migrate was beginning to evolve. Since then, the debate on migration in archaeology has not only reflected on patterns of cultural and technological change but also increasingly on aspects of identity and self-realisation; both in terms of how migrants themselves adapt and adjust to their new home environment, and how the host-communities themselves respond and interact with newcomers. Using four case studies, a proposed theoretical model for how to assess patterns of group migrations is proposed which considers their respective mode of agency, which is related to both the intention and size of the group. “Very High and High Group Agency” represent situations where the migrant group is at a technological and quantitative advantage to the host community, while “Medium and Low Group Agency” represent situations where the newcomers are forced to respond to their new environment through adaptation and adjustment to their local host community.