Decades of empirical research have shown that friendship experiences are an essential predictor of happiness. However, what might account for the relationship between friendship and happiness? Two studies investigated perceived mattering (Marshall, J Adolesc 24:473-490, 2001) as a mediator of the association between friendship quality and happiness. Study 1 showed that perceived mattering to one's best friend mediated the relationship between friendship and happiness. Study 2 replicated the findings of the first study and showed that mattering in friendships accounts for the role of friendship quality in happiness across the three closest friendships of the individual. The results are discussed in terms of the theoretical importance of understanding how friendship is related to happiness.