Digital technologies add a new dimension to economic, social, and cultural participation in contemporary society, and differences in their use may influence young people’s early experiences and trajectories within these domains. Having grown up in an era of widespread internet access, young people are often depicted as naturally competent and effective internet users, despite much evidence to the contrary (Buckingham, 2006). This thesis examines how and why young people vary in their engagement with the internet as they grow older and how these differences might impact on their developing life pathways. Research suggests that internet engagement is a process embedded within, and contributing to, broader processes of technological diffusion (Rogers, 2003; Compaine, 2001), social and cultural reproduction (Bourdieu, 1984; Hargittai, 2008) and individual reflexivity and adaptation (Giddens, 1984; Livingstone & Helsper, 2007). Accompanying each of these approaches are distinct ideas about what constitutes effective internet engagement and the types of factors differentiating young people in their internet use. In this thesis I develop a framework for explaining variation in youth internet engagement which attempts to reconcile key insights from existing approaches, whilst also addressing some of their limitations. I test this framework empirically using a mixed methods approach to illustrate different aspects of young people’s development as internet users over time. For this analysis I use survey and interview data from a large and representative cohort of secondary school students in Queensland, Australia who participated in waves 1 to 3 of the Social Futures and Life Pathways (‘Our Lives’) Project. These data were collected at various points in time, beginning in 2006 when research participants were aged 12/13 years and most recently in 2011 when they were aged 17/18 years. First, I examine differences in online time use at the beginning of high school with the overall cohort (n=6,545), before focusing on a core, longitudinal cohort (2,060) to investigate the extent and nature of their internet engagement at the end of high school. Then, in a series of qualitative interviews, I follow up with strategically chosen respondents (n=20) in the year following high school to explore how their perceptions and experiences of internet use vary. I reconcile findings from each of these approaches to identify three influential internet engagement pathways between adolescence and early adulthood, and the defining features of each: (1) a ‘preservation’ pathway, where mostly rural adolescents who experienced internet access barriers when they were younger became narrow and skeptical internet users; a ‘productivity’ pathway in which adolescents whose early use was subject to parental rules and regulation become narrow and disciplined internet users; and a ‘personality’ pathway, in which adolescents who experienced greater internet access and autonomy of use became broad, exploratory and confident internet users. I argue that each of these pathways contains features which can either help or hinder young people’s chances of engaging with the internet effectively, and call for further research identifying the social correlates and consequences of these pathways. Finally, I reflect on the implications of these findings for the policy context surrounding youth internet engagement in Australian society.