Mandibular metric and morphological characteristics have long been used for sex and ancestry estimation. Currently, there are no large‐scale studies examining interobserver agreement, particularly examining the role of observer experience. This study examines the interobserver agreement of six morphoscopic and eleven metric mandibular variables. Four observers with varied levels of experience scored 183 mandibles from the William M. Bass Donated Skeletal Collection. Absolute agreement and consistency were evaluated with the intraclass correlation coefficient (ICC). Additionally, technical error of measurement (TEM) and relative TEM (%TEM) were calculated for each metric variable. All analyses were conducted twice—once with all observers and again with only experienced observers. Results show mean morphoscopic agreement of 0.543 among all observers and 0.615 for experienced observers, and mean metric agreement of 0.886 among all observers and 0.911 for experienced observers. Further, no TEM exceeded 2 mm. All results were significant (p < 0.001).