In many cultures and for many centuries, the implications of birth order have been examined. Birth order has been shown to affect personality, accomplishments, and even career choice. This study investigated the impact of birth order and ethnicity on two measures of academic success in high school: a student’s grade point average (GPA) and the number of Advanced Placement (AP) classes he or she took. Based on previous studies, we hypothesized that birth order would have an effect on GPA and the number of AP classes taken. We also hypothesized that ethnicity would not affect this relationship. Survey results from 162 eleventh and twelfth grade students were analyzed by ANCOVA. Despite some prior research to the contrary, we found that birth order had no statistically significant effect on GPA or the number of AP classes taken. Although ethnicity affected GPA, there was no interaction between ethnicity and birth order effects, supporting our hypothesis that these particular birth order effects are not dependent upon ethnicity.