Institute of Gifted and Talented Students enrolls students according to their IQ levels. Although these students show high performance academically, they may experience underachievement in primary schools. The purpose of this study is to analyze the reasons for underachievement of gifted. The School Attitude Assessment Survey-R (McCoach, 2002) was applied to gifted students who are high achievers and underachievers. The sample consisted of 54 students from primary schools; 35 high achievers and 24 underachievers. Gifted achievers and gifted underachievers showed difference in their attitudes toward school, attitudes toward teacher, motivation, self-perception, and goal valuation. In addition, as the grade level increases, means of five sub factors of the instrument decrease for our sample. This study is an important step toward identifying factors related to the underachievement of gifted students in primary schools. (C) 2014 The Authors. Published by Elsevier Ltd.