The present study examined undergraduates’ attributions (control, responsibility and blame), emotional responses (anger and sympathy) and helping intentions (personal help and support for institutional assistance) towards PLHIV in Singapore. A 2 x 2 between-subjects design using vignettes systematically manipulated HIV onset controllability (high: casual sex / low: unfaithful spouse) and PLHIV gender (male/female). Two hundred fiftythree undergraduates from the National University of Singapore participated in the study. Significant main effects of HIV onset controllability were found for participants’ attributions, emotional responses and support for institutional assistance. A marginally significant main effect of HIV onset controllability was found for participants’ personal helping intentions. A significant main effect of PLHIV gender was found for participants’ sympathy. Participants’ emotional responses mediated the relationship between attributions of control and support for institutional assistance. Participants’ attitudes towards casual sex also moderated their anger and support for institutional assistance towards PLHIV with differing HIV onset conditions. Theoretical and practical implications are discusse
