There is increased recognition of the importance of children learning how to regulate emotions in a functional and adaptive manner for healthy psychological development. However, there is a paucity of tools for assessing emotion regulation during the middle childhood and adolescent years. This study reports on the psychometric evaluation of the 16-item self-report Emotion Regulation Index for Children and Adolescents (ERICA) involving a sample of 1,389 (768 girls, 621 boys) Australian children and adolescents aged 9 to 16 years. Convergent validity for the ERICA is reported with measures of self-conscious emotions (shame, guilt), empathy, childhood depressive symptomatology, and the perceived parenting dimensions of Care and Overprotection. Construct validity assessment using Principal Components Analysis and Confirmatory Factor Analysis yielded three factors: (1) Emotional Control, (2) Emotional Self-Awareness, and (3) Situational Responsiveness. The ERICA was also found to have good internal consistency and to be relatively stable over a four week test-retest period and to be sensitive to age and sex differences. It is concluded that the ERICA is a psychometrically sound measure for the assessment of the identified key aspects of emotion regulation in children and adolescents.