Background <p>Adolescence is a critical developmental period characterized by rapid neurobiological maturation and substantial changes in higher-order abilities, including vocabulary and logical thinking. Although prior research has documented general age-related improvements in these abilities, most studies have relied on cross-sectional or variable-centered designs, limiting insight into developmental heterogeneity and obscuring distinct developmental trajectories over time. Moreover, the relative importance of factors associated with these abilities across multiple ecological contexts—such as individual, family, school, and digital environments—remains insufficiently understood.</p> Objectives <p>This study aimed to identify distinct developmental trajectories of vocabulary and logical thinking abilities among Chinese adolescents and to examine the relative importance of factors associated with these trajectories across individual, family, school, and internet-related domains.</p> Methods <p>Data were drawn from the Chinese Family Panel Study (CFPS). A total of 662 adolescents (mean age at baseline = 12.14 ± 1.72&#xa0;years; 44.1% male) were followed longitudinally from early to late adolescence. Latent class growth curve modeling was used to identify developmental trajectories, and logistic regression and machine learning approaches were applied to examine associations and to rank the relative importance of influencing factors.</p> Results <p>Two distinct developmental trajectories were identified. The majority of adolescents exhibited relatively stable and improving trajectories of vocabulary and logical thinking abilities, whereas a smaller subgroup remained at lower levels across adolescence despite gradual improvement. Machine learning analyses consistently indicated that teacher satisfaction was most strongly associated with differences in developmental trajectories, followed by future confidence, parent–child communication, physical activity, and subjective well-being.</p> Conclusions <p>The findings highlight substantial heterogeneity in the development of adolescents’ vocabulary and logical thinking abilities and emphasize the relevance of the school environment—particularly teacher–student relationships—alongside individual emotional well-being and family contexts. Together, these results offer a nuanced perspective on developmental variability across adolescence and may help inform future research and practice aimed at understanding adolescents who follow less favorable developmental trajectories.</p>