While differences in injury risk between males and females have been highlighted using field data, sex differences in kinematic response and injury tolerance remain understudied in the literature. This study aimed to provide a sex-based comparison of pelvis kinematics, injuries, and lap belt interaction in frontal impacts of reclined occupants. Frontal sled tests were conducted with reclined mid-size adult PMHS (four male and three female). Forward or minimally rearward pelvis pitch (sagittal plane rotation) was observed in all seven subjects. Good engagement of the lap belt with the pelvis was observed;​ partial submarining was identified in one male test. Maximum forward pelvis displacement of the females exhibited greater variation than that of the males (115-174 mm vs. 139-159 mm). Two male PMHS and two female PMHS sustained iliac wing fractures resulting from belt loading. Due to variations in pelvis geometry compared to male subjects, the H-point positioning target for female subjects needed to be translated forward relative to that of the male subjects to fit the female subjects in the seat. Lap belt anchor points were also moved forward to avoid potential differences in belt–pelvis interaction. Nonetheless, the males and females generally displayed similar injury patterns and pelvis kinematics.