This study examined children's (N = 79; 9–10 years) and adolescents’ (N = 82; 15–16 years) ability to regulate their emotion expressions of anxiety as they completed a modified version of the Trier Social Stress Test for Children (TSST‐C). Approximately half in each age group were internationally adopted from institutional care (N = 79) and half were non‐adopted, age‐matched peers (N = 82). Institutional care was viewed as a form of early life stress. Coders who were reliable and blind to group status watched videos of the session to assess anxiety expressions using the Child and Adolescent Stress and Emotion Scale developed for this study. Children exhibited more expressions of anxiety than adolescents, and youth adopted from institutions showed more expressions of anxiety than their non‐adopted counterparts. The role of early life stress on observed anxiety expressions remained significant after controlling for differences in age, physiological stress responses measured through salivary cortisol reactivity, and self‐reports of stress during the TSST‐C. This suggests possible deficits in the regulation of expressive behavior for youth with early life stress histories, which cannot be explained by experiencing the task as more stressful.