Does being on the winning or losing side of an important national vote have an impact on well-being that is large or lasting? Previous studies have found mixed results. The current study was conducted over a 12-month period following the 2018 Irish abortion referendum. Participants (N = 1218) completed surveys at five time points; one week before the referendum, and one week, three months, six months, and twelve months after the referendum. We compared Yes and No voters’ subjective well-being (happiness and life satisfaction) at each time point, finding significant between-groups differences in happiness at wave 1 & 2 and in life satisfaction at wave 2. Further analyses showed weak correlations between measures of well-being and referendum-related variables (reported importance of the referendum, engagement with the campaign, etc.). The findings suggest a short-lived but significant effect of a referendum outcome on well-being, for both the winning and losing side.