This thesis represents four years of personal and professional development. Undertaking this research has enriched my understanding of the multifaceted social lives of Australian adolescents, and how their interactions within peer groups and dyads may influence their social and emotional well-being. The topic for this thesis emerged from an innate curiosity about the ways in which the fundamental human desire to belong may manifest for adolescents as different dynamics in their relations with peers. This curiosity, first recognised whilst completing my Honours research project for the Bachelor of Psychological Science, stemmed from a desire to inform both basic and applied research in the field. That is, whilst learning from adolescents who successfully fulfil the desire to belong I was able to simultaneously identify the maladaptive consequences for those in whom this goal is thwarted. Following successful completion of my Honours year, I committed to contribute further to research in this field and was fortunate to have this opportunity whilst undertaking the candidature for my PhD. Throughout this thesis, belongingness is an overarching theme, providing a lens through which to further understand how varying social and behavioural patterns may influence adolescent well-being. With its integration of traditional ideologies and modern research methods, this thesis and its associated publications, have contributed to research in the field of adolescent peer relations. I hope that through this research, adolescent well- being may be further empirically illuminated, via the examination of both social and emotional contributors, in order to provide further insight into its complexities at this distinctive developmental time.