We investigated the associations of individual’s compassion for others with his/her affective and cognitive well-being over a long-term follow-up. We used data from the prospective Young Finns Study (N = 1312‒1699) between 1997‒2012. High compassion was related to higher indicators of affective well-being: higher positive affect (B = 0.221, p < .001), lower negative affect (B = −0.358, p < .001), and total score of affective well-being (the relationship of positive versus negative affect) (B = 0.345, p < .001). Moreover, high compassion was associated with higher indicators of cognitive well-being: higher social support (B = 0.194, p < .001), life satisfaction (B = 0.149, p < .001), subjective health (B = 0.094, p < .001), optimism (B = 0.307, p < .001), and total score of cognitive well-being (B = 0.265, p < .001). Longitudinal analyses showed that high compassion predicted higher affective well-being over a 15-year follow-up (B = 0.361, p < .001) and higher social support over a 10-year follow-up (B = 0.230, p < .001). Finally, compassion was more likely to predict well-being (B = [−0.076; 0.090]) than vice versa, even though the predictive relationships were rather modest by magnitude.