BACKGROUND : The symptoms of lateral epicondylalgia (LE) can be persistent, and recurrence is frequent. Recurrence can be related to proximal segment impairment of the kinetic chain. Knowledge of any relation in the kinetic chain in LE may help treatment. We aimed to investigate scapular position and upper extremity muscle strength in patients with LE and to compare them with controls. METHODS : The study enrolled 51 patients with LE and 51 age-matched controls. We assessed scapular position asymmetry using the lateral scapular slide test and measured the strength of the upper trapezius (UT), middle trapezius (MT), lower trapezius, and serratus anterior muscles in addition to shoulder abduction, external rotation, and internal rotation and grip strength. RESULTS : The percentage of participants with scapular asymmetry was greater in the patients than in the controls (P = .005). The involved side regarding shoulder external rotation among the patients was significantly weaker than in the controls (P = .016, P = .009). The involved side of the LE patients was significantly weaker than the uninvolved side in terms of shoulder abduction, external rotation, and internal rotation (P = .013, P = .048, P = .013). The UT/MT ratio on the nondominant side of the controls was significantly greater than that on the involved side of the LE patients (P = .016). CONCLUSIONS : Upper extremity muscle strength, grip strength, UT/MT ratio, and scapular position are affected in patients with LE. In addition to the elbow, focusing on the upper segments is essential in the management of LE.