<p>Both theoretical models and empirical evidence suggest that children and adolescents with social anxiety disorder (SAD) have difficulties with emotion regulation (ER), but little is known about which deficits are disorder-specific or involved across different anxiety disorders for this age group. Furthermore, the available repertoire of ER strategies as an important component of ER flexibility has so far received little attention in research on this age group. Self-reported use of individual ER strategies, the overall repertoire of used ER strategies, and the ratio of adaptive and maladaptive ER strategies were assessed in children and adolescents (aged 10–15 years) with SAD (<i>n</i> = 60), clinical controls with specific phobia (SP, <i>n</i> = 41), and healthy controls (HCs, <i>n</i> = 63) in a cross-sectional study. Children and adolescents with SAD reported using several maladaptive ER strategies (e.g., giving up) more frequently and several adaptive ER strategies (e.g., problem-oriented action) less frequently than both other groups. No group differences in the amount of used ER strategies (repertoire) were identified, but children and adolescents with SAD were found to report a higher ratio of maladaptive and a lower ratio of adaptive ER strategies compared to both other groups. Results suggest that the extent of emotion dysregulation varies with disorder severity, with deficits being more pronounced in children and adolescents with SAD. Potential approaches for SAD treatment, including a shift in repertoire ratios, are discussed.</p>