A retrospective investigation was performed with use of cephalometric radiographs from eight patients with anterior maxillary advancement. Soft tissue changes associated with hard tissue changes were measured. Statistical description of soft tissue behavior in the upper lip was performed using correlation coefficients, regression functions, and ratios of change in the relationship of soft tissue to hard tissue. Ratios of change in relationship of soft tissue to hard tissue for three parameters of upper lip movement are proposed for clinical use in treatment planning. Further investigation of soft tissue behavior with orthognathic surgical procedures is indicated.