Background: YouTube is a widely accessible platform that facilitates the rapid dissemination of both evidence-based and potentially misleading health-related information. This study assesses the educational quality, reliability, and comprehensiveness of the most-viewed YouTube videos about scapular dyskinesis. Methods: A systematic search was conducted on YouTube using the keywords "scapular dyskinesia" and "scapular dyskinesis." The top 100 videos for each keyword were screened for inclusion, and the metrics, sources, and content of the included videos were analyzed. Video quality and reliability were assessed using the Global Quality Scale and the modified DISCERN scale, respectively. In addition, a newly developed, non-validated tool, Scapular Dyskinesis Specific Scoring, was used to provide a condition-specific content assessment. Results: The analysis revealed that 48.1% of the videos were low quality, and 62.0% lacked reliability. Videos produced by health-related websites exhibited superior quality. Content focusing on treatment and diagnostic approaches demonstrated significantly higher quality than other content categories (P<0.001). A correlation analysis indicated that the Video Power Index did not correlate significantly with reliability, quality, or comprehensiveness scores. Additionally, a simple regression analysis revealed that the video upload time negatively affected the quality, reliability, and comprehensiveness metrics. Conclusions: Most YouTube videos on scapular dyskinesis were of low quality, lacked reliability, and failed to provide comprehensive and accurate information. Furthermore, high-quality and reliable content tended to receive relatively low engagement and user preference scores. These findings underscore the urgent need for well-structured, evidence-based, and regularly updated YouTube content about scapular dyskinesis. Level of evidence: IV.