Anticipated regret has been implicated in health-related decision-making. Recent work on influenza vaccination has suggested that anticipated relief, too, may influence individuals' decisions to engage in positive health behaviours. To explore these affective components further and address the generality of possible mechanisms underlying these associations, we examined whether anticipated relief and anticipated regret independently predict testicular self-examination (TSE) intention and behaviour. Given claims about differences in their nature and function, we distinguished between counterfactual relief (relief that a worse outcome did not obtain) and temporal relief (relief that an unpleasant experience is over). Prospective correlational. At Time 1 (July 2022), 567 cis-gendered males were asked to complete measures of anticipated regret, anticipated counterfactual and temporal relief, measures of the Theory of Planned Behaviour and measures of anxiety and shame. One month later, the same participants were recontacted and asked about their engagement in TSE in the previous month. Anticipated counterfactual relief and anticipated regret are independent, positive, predictors of intention to engage in TSE and, indirectly, TSE behaviour itself. Interestingly, anticipated temporal relief was negatively associated with intention to engage in TSE and, indirectly, behaviour. Our results suggest that it may be the counterfactual nature of anticipated regret and anticipated relief that underlies their positive association with TSE and other health-promoting behaviours. Interventions designed to increase engagement in preventive health behaviours, such as TSE, may benefit from the consideration of both positively and negatively valenced counterfactual emotions.