Anticipated regret has been found to predict vaccination intentions and behaviours. We examined whether anticipated relief also predicts seasonal influenza vaccination intentions and behaviour. Given claims about differences in their antecedents 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). Cross-sectional. Unvaccinated participants (N = 295) were recruited online in November 2020. Participants completed measures of anticipated regret, anticipated counterfactual relief, and anticipated temporal relief and measures of theory of planned behaviour constructs (attitudes, norms, perceived control, and intentions). One month later, the same participants were re-surveyed and asked to report their vaccination status. Although all anticipated emotion measures were associated with intentions and behaviour, only anticipated counterfactual relief and regret independently predicted vaccination intentions in regression analyses. Mediation analysis showed both anticipated counterfactual relief and regret were indirectly, via intentions, associated with behaviour. Results suggest that, regardless of valence, counterfactual emotions predict vaccination intention and, indirectly, behaviour. Furthermore, participants may differ in their sensitivity to the anticipation of positive versus negative counterfactual emotions. These findings may permit more precise targeting of interventions to increase vaccine uptake.