Somatic symptom disorder has been a significant challenge among adolescents in secondary schools; however, there has been low awareness of sex relationships. This study, therefore, investigated the relationship between sex and somatic symptoms disorder among adolescents in secondary schools in Delta State. A research question was raised, and a corresponding null hypothesis was and a corresponding null hypothesis was also formulated to guide the study. The study employed a cross-sectional survey research design. The population of this study is 10,560 students in junior and senior secondary class II (JS II and SS II) from the fifty-two secondary schools in Ika North Local Government Area of Delta State as of the 2019/2020 academic session. A sample size of 600 students comprising three hundred (300) males and three (300) females was selected from 10 schools using the multi-stage sampling procedure. The research instrument for this study was the Adolescents Somatic Symptom Scale (ASSS), which was designed by Ebigbo (2016) and was adapted for use in this study. The researcher employed the Cronbach Alpha reliability method, and a reliability coefficient of 0.70 was obtained. Three test experts in Measurement and Evaluation revalidated the instrument, and the null hypothesis was tested at a 0.05 level of significance using the chi-square distribution. The study's findings show that Sex is not significantly related to somatic symptoms disorder. Based on the discovery, the researcher made the following recommendations, among others, that counsellors and psychologists should ensure early identification, intervention, treatment, and follow-up to avoid a resulting high risk of the disorder.