Hip arthroscopy has become a key procedure for treating femoroacetabular impingement (FAI) and associated intra-articular pathologies. While outcomes are generally favorable, some patients require revision surgery due to persistent pain, residual impingement, labral failure, or capsular insufficiency. Identifying the causes of failure—whether related to inadequate bone resection, labral pathology, or instability—is essential for planning a successful revision. This chapter outlines the evaluation and management of failed hip arthroscopy, emphasizing clinical assessment, imaging findings, and surgical techniques. Key aspects include addressing residual deformities, optimizing labral treatment, and restoring joint stability. Careful patient selection, precise execution, and structured rehabilitation are critical for improving outcomes in this challenging subset of patients. Recent advancements in diagnosing micro-instability, detailed cam deformity identification with three-dimensional (3D) reconstructions, and dynamic intraoperative assessments have enhanced the ability to detect subtle sources of failure, improving preoperative planning. Surgical techniques such as labral reconstruction, capsular augmentation, and optimized osteoplasty offer promising solutions for complex cases. A multidisciplinary approach, integrating patient education, individualized rehabilitation, and long-term monitoring, is crucial for maximizing function and preventing further complications.