Although many adolescents experience anxiety, few studies have examined anxiety trajectories separately for boys and girls or have attempted to understand the role of associated sociomotivational factors (SF). Based on self-determination theory, the present study aimed to identify trajectories of anxiety symptoms for boys and girls aged from 11 to 16 years and to explore whether these trajectories are predicted by academic competence, concerns about relatedness, and introjected regulation. A longitudinal sample of 493 adolescents (224 boys, 269 girls) took part in this study. Group-based trajectory analyses revealed three comparable trajectories for boys and girls (low, moderate, and high trajectory groups), as well as one trajectory unique to girls (moderate-increasing trajectory group). Concerns about relatedness were associated with the trajectory characterized by higher anxiety symptomatology in both boys and girls. Academic competence and introjected regulation, on the other hand, were related to the moderate-increasing trajectory for girls. (C) 2016 Elsevier Inc. All rights reserved.