What is the role of affect in social perception processes? This chapter reviews our empirical research programme on affective influences on social perception, and a new multi-process theoretical framework accounting for such effects is presented. In the first section, traditional approaches to research on social perception, and the recent affect-priming framework in particular, are outlined. Experimental results from our research programme on affective influences on social perception are reviewed next. The evidence shows robust and reliable mood effects on a variety of social judgements, from simple behaviour interpretation tasks to complex attribution and interpersonal preference judgements. The role of affect in social perception by children, in groups, and in field settings is also considered, and evidence for affective influences on processing strategies based on reaction-time studies is summarized. In the final section, recent affect-cognition theories are discussed, and a new integrative multi-process model is proposed. The implications of these results for everyday social judgements, and for contemporary models of social perception and cognition, are considered.