The purpose of this study was to investigate relationships between body mass index (BMI), physical fitness, and academic performance in elementary school students. Specifically, BMI and scores on the President's Challenge Physical Activity and Fitness Awards Program, a physical fitness test, were compared to reading and mathematics scores on the Florida Comprehensive Assessment Test (FCAT), a standardized norm-referenced academic achievement measure. Participants included 132 4th and 5th grade students from a k-12 school located in North Central Florida. Results revealed that BMI and physical fitness were correlated with academic performance for 5th grade females. In addition, there was a significant and negative association found between BMI and physical fitness across grade level and sex. (Contains 4 tables.)