The purpose of this study was to develop and test the psychometric properties of a Seizure Self-Efficacy Scale for Children (SSES-C). An initial pool of test items was generated using a variety of resources, including literature reviews, child self-efficacy measures from other chronic diseases, and self-efficacy measures for adult patients with epilepsy. Experts in the field of self-efficacy, chronic illness self-management, and behavioral management of seizure disorders were asked to evaluate item content and readability. The scale was administered via computer-assisted telephone interviews to 175 children ages 9 through 14 years who had had epilepsy for 6 months or more. Content validity of the SSES-C was ensured by 80% agreement on test items by experts. The final version of the scale has 15 items. Construct validity was supported by factor analysis and correlation of the SSES-C to other constructs of influence on the health behavior of children with epilepsy. Specifically, the SSES-C was significantly correlated with attitude toward illness, worry, unmet needs for psychosocial care, child depression, and child self-concept. Internal consistency reliability for the measure was also adequate (α =.93). The primary result of this study was the development of an easily administered and useful 15-item scale to measure the degree of self-efficacy experienced by children and adolescents related to the management of their seizure disorder. The SSES-C is a promising questionnaire that has potential for use as a clinical and research tool to measure self-efficacy in children with seizures.