To extend our understanding of the development of adolescent grit, we examined the relationships between social support and the two facets of grit (i.e., perseverance of effort and consistency of interest) and whether the relations were moderated by age and gender. Our sample was composed of 1475 Chinese adolescents with ages ranging from 10.65 to 19.24 years old (M-age = 14.98, SDage = 1.66). The results showed that social support was positively related to perseverance of effort but not significantly related to consistency of interest. However, these relations were moderated by age. Specifically, the effect of social support on perseverance of effort declined as age increased, but remained positive among late adolescents. Nevertheless, the effect of social support on consistency of interest was positive only among early adolescents, and the effect decreased and even became marginally negative among late adolescents. Gender difference was further examined, and the results show that the moderating role in the relationship between social support and perseverance of effort was only significant among males rather than females. That is, the positive effect of social support on perseverance of effort did not change with age among females. Theoretic and practical implications are discussed.