Although an important topic of discussion amongst parents, the impacts of screen use in toddlerhood and early childhood are not well studied. In particular, although some developmental outcomes (i.e., sleep and aggression in older children) have been considered in relation to screen time, much less is known about how screen time might affect prosocial behaviour, a key area of development in early childhood. The current prospective longitudinal study involved a sample of 195 (predominantly affluent and educated) families in the East of England and aimed to add clarity to discussions around screen time and prosocial behaviour by investigating the impacts of screen time on early empathic and sharing behaviour. Three main questions were addressed: (1) What is the landscape of technology use – how much technology are young children exposed to, what variety, and how does this change over time? (2) What patterns are seen across time and constructs in prosocial behaviour, and how do individual children vary in empathic concern and sharing behaviour? and (3) How do screen time, content, and screen format relate to prosocial behaviour in toddlerhood? Both mothers and fathers in the study completed interviews and questionnaires and semi- structured observations of children were taken at three time-points, when children were 14-, 24-, and 36-months of age. In addition, an objective coding scheme was developed and utilised to establish how much prosocial behaviour was portrayed in the programmes and films children were watching at age 24-months. In line with prior research and national organisational findings, children in the current study were exposed to screens from an early age and watched programmes that were often not rated as developmentally appropriate for their age group. In addition, while parents were typically able to evaluate levels of antisocial content in programmes, they showed less success at identifying contrasts across programmes in levels of prosocial behaviour. Expanding on a large body of research about longitudinal trends in prosocial behaviour, the current study found that children are capable of showing empathic concern from age two and being generous from age three; however, each of these measures showed marked individual differences. From 24-months to 36-months there was some stability in empathic concern. Finally, the current study suggests that the quantity of screen time is not wholly detrimental for prosocial behaviour in toddlerhood and there is evidence for a transfer deficit of social content for prosocial behaviour. The pacing of programmes appears to at least partially alleviate this deficit. All of the discussed findings have implications for families, policy-makers, and content-creators.