Big-fish-little-pond effect (BFLPE) research (e.g., Marsh & Parker, 1984) has found that perceptions of academic ability are generally positively related to individual ability and negatively related to classroom and school average ability. However, BFLPE research typically relies on environmental differences as a between-subjects factor. Unlike most previous BFLPE research, the current study used group average ability as a within-subject variable by measuring student self-concept before and after high-ability students left their regular school environment to participate in a supplemental academic summer program. Results revealed that academic self-concept (ASC) and educational aspirations did not undergo significant declines when students were in the relatively higher ability environment. Even with ceiling effects limiting potential increases in ASC, participants were more than 2 times as likely to increase or maintain their ASC as they were to report declines in ASC. Further, several boosts were found in nonacademic self-concepts. Such findings indicate that BFLPEs are not necessarily associated with supplemental educational environments. (Contains 2 tables, 3 figures and 3 footnotes.)