Social understanding and antisocial behaviour are each multi-faceted constructs; unravelling the connections between them could therefore fi ll an entire book. The aim of this chapter, therefore, is not an exhaustive review, but rather an “ assiette of ideas” that I hope will whet the reader’s appetite for more comprehensive fi ndings from individual lines of research. Specifi cally, the chapter is organized by fi ve points that are drawn from research in this fi eld. The fi rst of these is that theory-of-mind skills are socially neutral : although acquiring an understanding of mind is generally recognized as fundamental to more sophisticated social interactions, it is important to hold in mind that social consequences can be negative as well as positive. The second theme is that deviance as well as delay in children’s social understanding may affect social outcomes. That is, it may be more useful to ask whether processing of social information is biased (rather than simply delayed) in children with conduct disorder. The third theme concerns the importance of adopting a developmental perspective in order to assess whether early and late milestones in social understanding show distinct links with problem behaviours in childhood. The fourth theme is that links between social understanding and bullying are heterogeneous , refl ecting the different roles assumed by children who engage in (or are exposed to) bullying. The fi fth theme is that one promising avenue for expanding the scope of this research fi eld and making contact with research on adults is to bring deontics into the picture. That is, children’s understanding of social norms is likely to be at least as important an infl uence on their behaviour as their understanding of mental states; moreover, these two domains of knowledge appear to be closely entwined. Findings from the Toddlers Up study are outlined within several of these specifi c themes and brought together in the chapter summary.