Context: The fourth edition of the Preparticipation Physical Evaluation recommends functional testing for the musculoskeletal portion of the examination; however, normative data across sex and grade level are limited. Establishing normative data can provide clinicians reference points with which to compare their patients, potentially aiding in the development of future injury-risk assessments and injury-mitigation programs.Objective: To establish normative functional performance and limb-symmetry data for high school-aged male and female athletes in the United States.Design: Cross-sectional study.Setting: Athletic training facilities and gymnasiums across the United States.Patients or Other Participants: A total of 3951 male and female athletes who participated on high school-sponsored basketball, football, lacrosse, or soccer teams enrolled in this nationwide study.Main Outcome Measure(s): Functional performance testing consisted of 3 evaluations. Ankle-joint range of motion, balance, and lower extremity muscular power and landing control were assessed via the weight-bearing ankle-dorsiflexion–lunge, single-legged anterior-reach, and anterior single-legged hop-for-distance (SLHOP) tests, respectively. We used 2-way analyses of variance and χ2 analyses to examine the effects of sex and grade level on ankle-dorsiflexion–lunge, single-legged anterior-reach, and SLHOP test performance and symmetry.Results: The SLHOP performance differed between sexes (males = 187.8% ± 33.1% of limb length, females = 157.5% ± 27.8% of limb length; t = 30.3, P < .001). A Cohen d value of 0.97 indicated a large effect of sex on SLHOP performance. We observed differences for SLHOP and ankle-dorsiflexion–lunge performance among grade levels, but these differences were not clinically meaningful.Conclusions: We demonstrated differences in normative data for lower extremity functional performance during preparticipation physical evaluations across sex and grade levels. The results of this study will allow clinicians to compare sex- and grade-specific functional performances and implement approaches for preventing musculoskeletal injuries in high school-aged athletes.