This study investigated the relationship among lack of self-control, academic ability, and academic performance for a cohort of freshman engineering students who were, with a few exceptions, extremely high achievers in high school. Structural equation modeling analysis led to the conclusion that lack of self-control in high school, as measured by the frequency of illegal and irresponsible behaviors, had an inverse relationship with first semester grade point average (GPA), whereas academic ability, as measured by ACT scores, had a positive relationship with college GPA. The correlation between the residual error for one of the indicators of self-control, homework behaviors in high school, and the residual error for first semester GPA was also significant. Research on the relationships between self-control, homework behaviors in high school, and performance in college should continue; meanwhile, parents and teachers would be advised to emphasize the importance of developing self-control and positive homework behaviors in academically advanced high school students. (Contains 7 tables and 2 figures.)