© by the National Athletic Trainers' Association, Inc. Context: Deficits in dynamic postural control predict lower limb injury. Differing fatiguing protocols negatively affect dynamic postural control. The effect of high-intensity, intermittent exercise on dynamic postural control has not been investigated. Objective: To investigate the effect of a high-intensity, intermittent exercise protocol (HIIP) on the dynamic postural control of men and women as measured by the Star Excursion Balance Test (SEBT). Design: Descriptive laboratory study. Setting: University gymnasium. Patients or Other Participants: Twenty male (age = 20.83 ± 1.50 years, height = 179.24 ± 7.94 cm, mass = 77.67 ± 10.82 kg) and 20 female (age = 20.45 ± 1.34 years, height = 166.08 ± 5.83 cm, mass = 63.02 ± 6.67 kg) athletes. Intervention(s): We recorded SEBT measurements at baseline, pre-HIIP, and post-HIIP. The HIIP consisted of 4 repetitions of 10-m forward sprinting with a 90° change of direction and then backward sprinting for 5 m, 2 repetitions of 2-legged jumping over 5 hurdles, 2 repetitions of high-knee side stepping over 5 hurdles, and 4 repetitions of lateral 5-m shuffles. Participants rested for 30 seconds before repeating the circuit until they reported a score of 18 on the Borg rating of perceived exertion scale. Main Outcome Measure(s): A mixed between- and within-subjects analysis of variance was conducted to assess time (pre-HIIP, post-HIIP) x sex interaction effects. Subsequent investigations assessed the main effect of time and sex on normalized maximal SEBT scores. We used intraclass correlation coefficients to determine the test-retest reliability of the SEBT and paired-samples t tests to assess the HIIP effect on circuit times. Results: We found a time x sex effect (F8,69 = 3.5; P range, <.001-.04; η2 range, 0.057-0.219), with women less negatively affected. We also noted a main effect for time, with worse normalized maximal SEBT scores postfatigue (F8,69 = 22.39; P < .001; η2 range, 0.324-0.695), and for sex, as women scored better in 7 SEBT directions (F8,69 = 0.84; P range, <.001-008; η2 range, 0.088-0.381). The intraclass correlation coefficients demonstrated high (0.77-0.99) test-retest repeatability. Paired-samples t tests demonstrated increases in circuit time post-HIIP (P < .001). Conclusions: The HIIP-induced fatigue negatively affected normalized maximal SEBT scores. Women had better scores than men and were affected less negatively by HIIP-induced fatigue.