--- - |2 This study explores how the age (adult vs. peer) and the suggestion (to be fair vs. unfair) of models affect the sharing decisions of 9‐ and 12‐year‐olds (N = 365) from Italy and Singapore. Results demonstrate a developmental shift in the influence of models on children's and adolescents’ sharing decisions in both cultures: Children's decisions were more affected by an adult model's suggestion than by that of a peer model, whereas the opposite was true for adolescents. Regardless of the models’ influence, participants considered equal sharing to be the fair choice and reported being happier when their sharing decisions were generous. Our results highlight the crucial importance of social and developmental factors for the promotion of fairness judgments and emotions. - Child Development, Volume 89, Issue 5, Page 1589-1598, September/October 2018.