Subacromial Impingement Syndrome (SAIS) is a common shoulder condition characterized by pain and functional impairment. Proprioception, the sense of joint position and movement, is crucial in maintaining joint stability and coordinating movements. The relationship between shoulder proprioception, pain intensity, and functional disability in individuals with SAIS remains unclear, with conflicting findings in the literature. This cross-sectional study aimed to evaluate shoulder proprioception, examine its correlation with pain intensity and functional disability, and contribute to our understanding of the clinical implications of proprioceptive deficits in individuals with SAIS. Forty-two individuals were diagnosed with SAIS, and an equal number of asymptomatic controls were recruited. Shoulder proprioception was assessed using a digital inclinometer, measuring joint position sense at various angles of flexion and rotation. Pain intensity was measured using the Visual Analog Scale (VAS), and functional disability was assessed using the Shoulder Pain and Disability Index (SPADI). Results: Individuals with SAIS exhibited significantly higher joint position error (JPE) values compared to asymptomatic controls in all measured angles of flexion and rotation (p< 0.001). Strong positive correlations were observed between JPE and pain intensity (r = 0.61 to 0.71,p< 0.01) and disability (r = 0.56 to 0.68,p< 0.01). These findings suggest impaired shoulder proprioception is associated with higher pain intensity and functional disability in SAIS. This study provides evidence of impaired shoulder proprioception in individuals with SAIS and its correlation with pain intensity and functional disability. The results highlight the clinical relevance of proprioceptive deficits in SAIS and emphasize the importance of incorporating proprioceptive assessment and targeted rehabilitation interventions into managing this condition. Future research should focus on longitudinal studies with larger and more diverse samples to further understand the underlying mechanisms and evaluate the effectiveness of proprioceptive interventions in improving outcomes for individuals with SAIS.