People begin to become aware of their sexual drive and erotic feelings as young adolescents. Such activity often has been overlooked in Taiwan, a traditional society, because sexuality is viewed as a private issue. The purpose of this study was to explore the sexual self-concept and intended sexual behavior of young adolescent girls in Taiwan. Participants included 372 girls, 12 to 14 years old, from junior high schools in Taiwan who completed two questionnaires on sexual experience and sexually related items: the Sexual Self-Concept Inventory, the Parental Approval of Sexual Behavior Scale, and the Friends' Approval of Sexual Behavior Scale, which were combined into one scale, with separate scores. Girls' self-reports showed low (negative) sexual self-concept, high perceived parental disapproval, and somewhat high perceived friends' disapproval of sexual activities. Sexual self-concept is associated with perceived parental and peer approval of sexual activities, and it is associated with sexual experience and intended sexual activities as well. A young adolescent girl who has a high score on the perceived sexual arousability factor of the Sexual Self-Concept Inventory is more likely to report the strongest intention toward sexual behavior. Sexual self-concept may play a key role in girls' intended sexual activities, including engaging in low-level sexual activities (e.g., kissing and breast fondling) that occur before intercourse, even when associated with intercourse intention. The research suggests that addressing sexual self-concept needs to be a priority to prevent young girls from engaging in sexual intercourse.