Objective <p>This study aimed to investigate the effects of scapular stabilization exercises on pain, shoulder function, and daily activities in individuals with subacromial impingement syndrome.</p> Methods <p>Sixty-three participants (18–65&#xa0;years) with clinically diagnosed subacromial impingement syndrome were included in this prospective controlled clinical study. Subjects were randomly assigned to the control group (<i>n</i> = 32; standard physiotherapy) or intervention group (<i>n</i> = 31; physiotherapy plus scapular stabilization). Assessments at baseline, week 6, and week 12 included the Visual Analog Scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (Quick DASH) questionnaire and Modified Constant-Murley Score.</p> Results <p>Both groups improved, but the intervention group achieved significantly better outcomes. At week 12, Constant score was higher (<i>p</i> = 0.048), QuickDASH was lower (<i>p</i> = 0.009, <i>p</i> = 0.003), and VAS scores at rest, movement, and night were reduced (all <i>p</i> &lt; 0.05). The intervention group achieved greater functional improvement and pain reduction, reflected by differences of 0.313 in QuickDASH, 0.498 in rest pain, and 1.128 in movement pain. A minor decrease in movement pain (–0.067) was also seen in participants with higher BMI.</p> Conclusion <p>Scapular stabilization added to physiotherapy led to greater improvement in pain, functional scores, and daily activity performance than physiotherapy alone, indicating that targeted scapular training enhances clinical outcomes in subacromial impingement syndrome.</p> Trial registration <p> ClinicalTrials.gov Identifier: NCT07277868.</p> Level of evidence <p>I.</p>