IntroductionThe present study examined predictors of negative changes in weight control intentions from before to during the COVID‐19 pandemic among adolescents.MethodsParticipants were Canadian secondary school students enrolled in the COMPASS study and had completed self‐report surveys before (T1; 2018/2019 and/or 2019/2020 school year) and during (T2; 2020/2021 and/or 2021/2022) the COVID‐19 pandemic (N = 11,869, Mage ± SD = 13.79 years old ± 1.15, 52.89% girls, 45.30% boys, 1.81% gender diverse). Demographic, interpersonal, behavioral, and psychological predictors of weight control intention change from T1 (stay the same weight, not doing anything about weight) to T2 (lose weight, gain weight) were tested using multilevel logistic regressions.ResultsOver one‐third (37.0%) of adolescents who reported wanting to stay the same weight at T1 changed their intention to lose or gain weight at T2, as did 28.5% of adolescents who reported wanting to stay the same weight at T1. Changing weight control intention from “not doing anything about weight” at T1 to weight gain/loss at T2 was associated with resistance training, emotion dysregulation, bullying, social media use, and gender. Changing weight control intention from “stay the same weight” at T1 to weight gain/loss at T2 was associated with gender, perceived financial comfort, social media use, and flourishing.ConclusionsResults highlight the prevalence of maladaptive weight control intention changes among adolescents, and elucidate related behavioral, interpersonal, demographic, and psychological factors. Findings can inform targeted intervention and prevention strategies to disrupt maladaptive changes in weight control intentions among high‐risk subgroups.