Competency‐based teasing has been identified as a risk factor for children's depressive symptoms. However, the specific psychological mechanisms mediating this relationship are not well understood, especially in the context of Chinese culture. This study examined the relationship between competency‐based teasing, subsequent depressive symptoms, and the possible mediating role of positivity in Chinese children by using parallel process latent growth curve modelling. Gender differences were also explored. A sample of 4376 Chinese children (55.1% boys; age: M = 9.98 years, SD = 0.88) completed measurements of the relevant constructs on five occasions across 2 years, using half‐year intervals. The findings revealed that competency‐based teasing was significantly positively associated with subsequent depressive symptoms in Chinese children. Furthermore, positivity mediated this relationship in girls, but not in boys. The results suggest that positivity‐cultivating and gender‐specific interventions may be effective to reduce the risk of depressive symptoms in Chinese children.