The study explored whether delay of gratification measured in 6-year old preschool children, incrementally predicts their subsequent academic achievement and social acceptance in elementary school above cognitive abilities. The role of gender in this relationship was also examined. The sample comprised 99 girls and 120 boys attending fourth, fifth and sixth grades. The study was longitudinal with two measurement points: measures of cognitive abilities and delay of gratification were taken at the age of 6, while measures of academic achievement (GPA, grade in Croatian language and math) and social acceptance, measured with the sociometric technique, were taken between the age of 10 and 12 years. It was confirmed that delay of gratification predicted both subsequent academic achievement and social acceptance in elementary school above cognitive abilities, but more strongly for boys than for girls. Also, delay of gratification mediated the relationship between gender and all four dependent variables. Gender differences in social acceptance, Croatian and math grades were partially explained and gender differences in GPA were fully explained by gender differences in delay of gratification measured at preschool age.