To test the hypothesis that personality structure differs across levels of cognitive ability, personality traits of 154 participants of various ages and educational backgrounds were rated by themselves and two well-informed judges using the Estonian Personality Item Pool NEO (EPIP-NEO; Mõttus, Pullmann, & Allik, 2006). When participants were divided into two groups on the basis of their ability test scores, a relatively high cross-observer agreement was observed in the both ability groups. Although in the high-ability group personality traits were slightly less correlated and factor structures were somewhat more similar to the normative American self-report structure of the NEO-PI-R, there was no evidence that personality structure differs substantially across ability groups.