The objective of this study was to determine the force transmitted to the mandible from the chin strap in football helmets for head impacts. A total of 32 tests were performed comparing front and side impact locations. Each location was tested at two impact velocities (6.5 m/s and 9.0 m/s). Different combinations of neck collars and shoulder pads were tested at each speed and location to account for potential equipment variability between football players. A 50th percentile male Hybrid III dummy was equipped with a helmet, shoulder pads, and various neck collars. Tension load cells were installed on the left and right sides of the chin straps. From the tension values in the chin strap, the force transmitted to the mandible was calculated. With the front impact location, the average peak mandible load was 568 +/- 80 N at 6.5 m/s and 806 +/- 64 N at 9.0 m/s. With the side impact location, the average peak mandible load was 87 +/- 36 N at 6.5 m/s and 170 +/- 80 N at 9.0 m/s. Although there are some overlying assumptions, these values represent a good estimation of the forces acting on the mandible for head impacts in football.