The topic of underachievement and how to reverse it has received a great deal of attention in the gifted education literature. The present study sought to add to the knowledge base on this issue by investigating the occurrence of underachievement behaviors and their predictors in a population of highly gifted students attending a summer educational program based on the talent search model. A group of 440 students in Grades 8-10 were given the "School Attitude Assessment Survey--Revised" at the beginning of the program. Attitudes toward and grades obtained in students' regular schools had little to no predictive value on students' academic and behavioral performance during the summer program. Results support qualitative findings in the literature, suggesting that educational interventions can be extremely effective in reversing the expression of underachieving behaviors. (Contains 8 tables.)