The role of emotion within the reformulated Social Information Processing (SIP) Model of Children’s Social Adjustment (Crick and Dodge, 1994) has not been well investigated, particularly for young children. A developmental model of SIP and emotion proposed by de Castro (2010), provided the theoretical foundation for the current study to incorporate emotion processing variables into a pre-existing SIP interview for preschool children (SIPI-P, Ziv and Sorongon, 2011). The primary aims of this study were to (1) investigate age differences across social and emotional information processing between early childhood and early primary school aged children, (2) to describe the associations among children’s social and emotional information processing and behavioural characteristics, and (3) to replicate and extend the results of Helmsen,Koglin, and Petermann(2012) by examining the relationship between regulation (emotion and behavioural), information processing (social and emotional), and child behavioural difficulties (externalising and internalising). Two cohorts of children were recruited (30 children aged 4 years old and 30 children aged 6 to 7 years old), who were administered an expanded SIPI-P interview and a self-regulation task. In addition, children’s parents completed a questionnaire assessing internalising and externalising behaviours and emotion regulation. The results showed very few differences between the two groups of children for SIP, but consistent differences for emotion processing. Younger children rated aggressive responses more favourably, perceived more emotional intensity in the hypothetical vignettes, and showed lower levels of emotional reasoning and perspective taking skills when compared to the older children. Results also showed rather distinct patterns of associations for the two groups between social and emotion processing variables and behavioural and regulatory measures. For the preschool aged children there were consistent substantive associations between behavioural regulation and the social and emotion information processing variables, but very few associations with emotion regulation and internalising or externalising behaviours. For the early primary school aged children, there were several substantive associations between the social and emotion information procesing variables and internalising behaviours, but very few associations with behaviour regulation, emotion regulation, or externalising behaviours. Finally, when emotion information processing and emotion regulation were jointly tested as predictors of internalising behaviours with the primary school children, the results showed that only emotion regulation remained a significant predictor. Overall, the inclusion of emotion understanding variables in a social information processing interview format demonstrated that parsimonious integration of the two areas is both achievable and successful in yielding useful research information and suggests that the SIP model may be effectively used to explore other domains of social cognition and social competence.