The purpose of the present study was to explore the role of horizontal lip position in the evaluation of beauty in a lateral facial profile. The sample size of 1,000 students were randomly selected from all the Junior High Schools in the city of Taipei. One hundred and ten 12-year-old students were judged to be good looking and were selected by 7 panelists of different educational backgrounds. The 110 good-looking students were composed of 83 males and 27 females. Absolute horizontal lip position (the shortest distance between tip of lip and the reference line used) and relative horizontal lip position (the difference between lower and upper lip position) were analyzed between males and females, then between the good-looking group and the non-good-looking groups. The following conclusions were drawn from the results: 1. The requirement on the soft-tissue lateral profile of females is more straight than that of males. 2. According to Ricketts' E line, Steiner's S1 line and Burstone's B line, the relative lip position between 0 to +2 is acceptable to most people. 3. Fullness of lips is more readily accepted by people for males than females. 4. Further investigation of the effectiveness of Holdaway's H line and Sushner's S2 line is desperately needed. Their reference consistency vibrated a lot in this study.