Despite cultural and individual variation, humans are a judgmental bunch 1. There is accumulating evidence for early social and moral evaluation as shown by research with infants and children documenting the notion that some behaviors are perceived as right and others are perceived as wrong 2. Moreover, social interactions are governed by a concern for fairness and others’ well-being 3, 4. However, although generosity increases between infancy and late childhood, it is less clear what mechanisms guide this change 5. Early predispositions toward prosociality are thought to arise in concert with the social and cultural environment, developing into adult morality, a complex incorporation of emotional, motivational, and cognitive processes 6, 7. Using EEG combined with eye tracking and behavioral sharing, we investigated, for the first time, the temporal neurodynamics of implicit moral evaluation in 3- to 5-year-old children. Results show distinct early automatic attentional (EPN) and later cognitively controlled (N2, LPP) patterns of neural response while viewing characters engaging in helping and harming behaviors. Importantly, later (LPP), but not early (EPN), waveforms predicted actual generosity. These results shed light on theories of moral development by documenting the respective contribution of automatic and cognitive neural processes underpinning social evaluation and directly link these neural computations to prosocial behavior in children. •Temporal dynamics of morality in 3–5 year olds are examined with EEG and eye tracking•Distinct early and later controlled waveforms in viewing helping and harming scenes•Later (LPP), but not early (EPN), waveforms predicted actual generosity•These results shed important light on theories of moral development Prosocial behavior emerges early in development, and young children possess capacities for social and moral evaluations. In this study, Cowell and Decety explored their neural underpinnings in 3–5 year olds and how these predict actual generosity, exemplifying the potential of integrating development and neuroscience in refining moral theories.