Despite the recognized importance of emotion regulation (ER) for healthy psychological development, ER research has focused predominantly on the developmental periods of infancy, early childhood, and adulthood, while the middle childhood to adolescence years have been relatively neglected. An obstacle to ER research during these periods is the paucity of valid age-appropriate measures. This study reports on the psychometric evaluation of the Emotion Regulation Questionnaire for Children and Adolescents (ERQ-CA), a revision of the adult measure. The ERQ-CA was evaluated with a sample of 827 participants aged between 10 and 18 years. Results indicate sound internal consistency as well as stability over a 12-month period. Sound construct and convergent validity are also demonstrated. It is concluded that the ERQ-CA is a valid age-appropriate measure for investigating the use of 2 specific strategies of ER during the childhood and adolescence developmental periods. (Contains 1 figure and 4 tables.)