Riverbank erosion is a multifaceted and dynamic phenomenon that presents considerable hazards to communities and infrastructure adjacent to river bank. This chapter defines and applies the main ideas of the theoretical investigation and examines in a critical manner about the patterns of livelihood risks and vulnerabilities of Internally Displaced Persons (IDPs) caused by riverbank erosion in Bangladesh. This chapter consists of a thorough literature review that is relevant to the research context, and primarily aims to identify and discuss essential concepts used in the study. The chapter also examines the theoretical models and frameworks that are closely linked, and aims to establish a conceptual framework that may serve as the guiding principle for the current study and provide an explanation of the framework.