This thesis examines the effectiveness of imagined intergroup contact at promoting intergroup helping behaviour. Theoretically, it is argued that by adopting a third-person perspective in the imagined contact task prosocial action can be facilitated across intergroup boundaries. The results of eight studies provide evidence that imagining prosocial contact from the third-person perspective increased prosocial attitudes and actions. Additionally, results revealed that the imagined helping did not need to be specific to a particular group, or even an intergroup encounter: Any imagined helping scenario subsequently enhanced specific and generalised attitudes towards helping others, and increased the likelihood of observing prosocial behaviour. Importantly these effects were observed in laboratory and field studies, in the UK and Malaysia, and with majority and minority groups. Overall, this thesis contributes to a greater understanding the impact of mental simulation on enhancing prosocial attitudes and behaviours, and helps explain how and why imagined contact can encourage intergroup helping in a range of experimental and real-life contexts.