Although ample research evidence exists regarding the negative association between body dissatisfaction and body appreciation, the longitudinal association between these two constructs remains unclear, especially for adolescents. Thus, this study investigated the longitudinal association between body dissatisfaction and body appreciation and potential gender differences in this relationship in Chinese adolescents using four-wave longitudinal data. A sample of 2566 adolescents (54.10% girls) were included. A Random Intercept Cross-Lagged Panel Model (RI-CLPM) was conducted separately for boys and girls after controlling for baseline age and BMI z-scores. Results at the within-person level showed that for boys, body dissatisfaction at each wave negatively predicted body appreciation at the following wave, and body appreciation at Wave 2 and Wave 3 negatively predicted body dissatisfaction at Wave 3 and Wave 4. For girls, at the within-person level, body dissatisfaction at Wave 1 and Wave 2 negatively predicted body appreciation at Wave 2 and Wave 3, and body appreciation at Wave 3 negatively predicted body dissatisfaction at Wave 4. However, no gender differences in the RI-CLPM were found. The current findings enrich positive and negative body image research by providing evidence for the reciprocal relationships between body dissatisfaction and body appreciation in Chinese adolescents.