The purpose of this study was to examine the psychometric properties of the Adolescent Dissociative Experiences Scale (A-DES) applied to Japanese adolescents in school. A large sample of normal adolescents (N = 2,272) aged 11 to 18 years completed the A-DES, and the factor structure, frequency, and differences by gender and age were examined. The scores of Japanese adolescents were comparable to the results of similarly aged adolescents in the United States, England, and Turkey but much higher than those recorded in The Netherlands, Finland, and Sweden. In particular, adolescents aged 11 to 12 seemed to have more dissociative experiences than older adolescents. Out of 1-, 2-, 3-, and 4-factor structures that exploratory factor analyses regarded as competing models, confirmatory factor analyses seemed to support a 3-factor structure: depersonalization, disintegration of conscious control, and amnesia. The future implications of these results for clinicians and professionals who assess dissociative tendency in adolescents are described.