The current study examined the relationship between gifted adolescents' overexcitabilities and self-concept, while also exploring gender and grade-level differences in overexcitabilities. Participants included 248 gifted adolescents who had completed the sixth through tenth grade during the previous academic year. Overexcitabllities were measured using the Overexcitabilities Questionnaire-Two (Falk, Lind, Miller, Piechowski, & Silverman, 1999). Multiple facets of self-concept were measured using the Self Description Questionnaire II (Marsh, 1990). Females reported higher sensual, imaginational, and emotional overexcitability subscale scores than males. Grade-level differences were found for intellectual overexcitability. There were no gender or grade level differences for psychomotor overexcitability. Results indicate multiple relationships between overexcitabilities, self-concept, and grade level. Conclusions and implications are discussed. (Contains 7 tables and 2 endnotes.)