The aim of this study was to measure the location of the septoaponeurosis junction relative to the tarsal plate in the upper eyelids of Koreans through a histologic study.Thirty-four upper eyelids from 34 Korean adult cadavers (mean age, 77.8 years) were used. Sagittal sections on the midpupillary line were made, and 10-μm-thick sections were prepared and stained with hematoxylin-eosin and Masson trichrome. Under a magnifying loupe with a scale, the height of the tarsal plate (HTP), thickness of the tarsal plate (TTP), distance from the lid margin to the septoaponeurosis junction (MJD), and distance from the upper border of the tarsal plate to the septoaponeurosis junction (TJD) were measured.The mean HTP was 8.09 ± 1.68 mm (range: 4.0-0.8 mm). The mean TTP was 1.52 ± 1.56 mm (range: 0.8-3.0 mm). The mean MJD was 9.18 ± 2.69 mm (range: 2.5-13.0 mm). The mean TJD was 1.1 ± 2.6 mm (range: -5.5-7.0 mm). In 25 (73.5%) of the 34 eyelids, the SAJ (1.1 ± 2.6 mm) was above the upper border of the tarsal plate (UTP); however, in 9 (26.5%) of the 34 eyelids, below the UTP. The greater the HTP, the greater the MJD was (y=0.620x+4.166, P = 0.024 [linear regression analysis]). However, there was no significant correlation between the HTP and TJD (P = 0.155 [correlation analysis]).The results of this study provide a useful guide for performing operations involving the orbital septum and levator aponeurosis.