The purpose of this study was to investigate the cognitive and behavioral profiles of high ability students. Performance on measures of verbal and visuo-spatial working memory and general ability (vocabulary and block design) was compared across the following groups: high, average, and low ability students. The behavioral profile of high ability students was also compared with those with a clinical diagnosis of ADHD. The working memory performance was superior in the high ability students compared to the low and average ability groups, though the relationship between working memory and IQ weakens as a function of increasing ability. The findings are discussed in light of Spearman's law of diminishing returns. The behavioral profile of this group indicates similar features in some respects to those with a clinical diagnosis of ADHD, however, underlying explanations may differ and should be taken into consideration in future research on dual needs in high ability students. (Contains 3 tables.)