The aim of this study was to assess the mean overjet in school-going Libyan children and to examine the relationship between increased overjet and permanent incisor's trauma.This study is a part of a cross-sectional investigation of aspects of dental health of 2015 school going Libyan children aged between 6 and 16 years old of both genders from both rural and urban areas. Overjet was measured as the horizontal distance in millimetres between the upper and lower incisors. Trauma to permanent incisors was assessed according to Elli's Classification.SPSS version 20.0 for percentages was used for statistical analysis. The relationship between increased overjet and incisor trauma was tested using the Chi-square test at 0.05 significance level. The overjet measurement ranged from -2 mm to 8 mm with the mean overjet of 3.062 (1.23, SD). The prevalence of incisor trauma was statistically significantly higher in children with increased overjet (P < 0.0001).The average mean overjet value in Libyan children is between 2 mm and 3 mm and below or above these values, considered decreased or increased, respectively. Traumatic injuries to permanent incisors significantly increased with increased overjet.