The rapid uptake of the internet has provided a new platform for people to engage with almost all aspects of life. As such, it is currently crucial to investigate the relationship between the internet and cognition across contexts and the underlying neurobiological mechanisms driving this. We describe the current understanding of this relationship across the literature and outline the state of knowledge surrounding the potential neurobiological drivers. Through focusing on two key areas of the nascent but growing literature, first the individual- and population-level implications for attention processes and second the neurobiological drivers underpinning internet usage and memory, we describe the implications of the internet for cognition, assess the potential mechanisms linking brain structure to cognition, and elucidate how these influence behaviour. Finally, we identify areas that now require investigation, including (i) the importance of the variation in individual levels of internet usage, (ii) potential individual behavioural implications and emerging population-level effects, and the (iii) interplay between age and the internet-brain relationships across the stages of development.