Objectives: This study aimed to describe the trends of the muscle-strengthening exercise (MSE) guidelines adherence in adolescents and factors associated with the adherence.Methods: Using the Youth Risk Behavioural Survey data, this study assessed the trends of adhering to the MSE guidelines in adolescents. The survey-year-based trends of MSE guidelines adherence was assessed with logistic regression. Binary logistic regression was used to identify the correlates (i.e., sex, grade, race/ethnicity) of the guidelines’ adherence.Results: 73,074 study participants (female = 36,497, male = 36,108; mean age = 16.04 years) were included for analysis. An overall declining trend of the MSE guidelines in adolescents was found (55.6% in 2011 → 49.5% in 2019, p < 0.001), and similar trends were observed in both sexes. The declining trends varied by sociodemographic factors (e.g., grade). Boys and younger adolescents were more likely to adhere to the MSE guidelines.Conclusion: The declining trend of adhering to MSE guidelines in US adolescents would be a health concern in this population. Girls and older adolescents should be targeted as intervention priorities.