Purpose: Upper extremities are essential to perform activities of daily living. Along with many factors, the spinal region has an important effect on performing upper extremity movements. Our study's first aim was to examine the relationship between unsupported upper extremity exercise capacity (UUEEC) and spinal mobility. The second aim of the study was to determine whether spinal mobility is a predictor of the UUEEC. Methods: Forty asymptomatic and volunteer individuals (age=21.50±1.51 years, 52.5% of females) were included in the study. The 6-minute pegboard and ring test (6PBRT) was performed to assess the UUEEC. Spinal mobility was assessed to use a hand-held, computer-assisted electromechanical device (the Spinal Mouse System, Idiag, Fehraltorf, Switzerland). The spinal mobility analysis in the sagittal (SAP - maximal extension/flexion) and the coronal (CRP - maximal left/right lateral flexion) plane was measured. Results: The 6PBRT score had a moderate and positive correlation with the SAP spinal mobility (r=0.361, p=0.022) and the CRP spinal mobility (r=0.322, p=0.043). Stepwise multiple linear regression analysis demonstrated that the SAP spinal mobility was a significant and independent predictor of the 6PBRT score with 11% of the variance. Conclusions: The SAP spinal mobility was found as a predictor of the UUEEC in asymptomatic individuals. This study demonstrates that UUEEC could be improved by increasing spinal mobility.