Background: These days, we can't imagine living without our smartphones. Physical functions of your hands and fingers like dexterity and coordination could be impaired from too much time spent on your smartphone due to the constant grasping and tapping of its screen. Objective: The purpose of this study was to look into how smartphone addiction affects normal adolescent students' manual coordination (manual dexterity and upper limb coordination), grip strength, pinch strength, and wrist and hand pain. Subjects and Methods: An observational cross-sectional study for governmental and private preparatory and secondary schools at Ashmoun educational administration, Menoufia Governorate, Egypt was done. The study included one hundred normal teenage students (54 girls and 46 boys), aged from 12 to 18years. The Bruininks-Oseretsky Test of Motor Proficiency was employed to evaluate manual coordination (manual dexterity and upper limb coordination) (BOT-2). A hand dynamometer and a pinch meter were used to measure grip and pinch strength. The PRWHE questionnaire was used to assess wrist and hand pain as reported by participants. Results: Research found a significant positive association between smartphone addiction ratings and pain in the wrist and hand (r = 0.304, P = 0.002). Scores on a scale measuring smart phone addiction were not significantly correlated with any of the other characteristics studied. Conclusion: In a typical sample of adolescent students, researchers observed a significant positive association between smartphone use and wrist/hand pain. This finding indicates that the heavy usage of smartphones is considered a risk factor that leads to wrist/hand pain.