Background: Total Hip Arthroplasty (THA) in younger patients presents unique challenges due to higher functional demands and longer life expectancy. This systematic review aimed to evaluate long-term outcomes of THA in patients aged 50 or younger. Methods: We searched multiple databases for studies reporting outcomes of THA in younger patients with a minimum 10-year follow-up. Two independent reviewers assessed study quality and extracted data on implant survival, functional outcomes, complications, and patient-reported measures. Results: Seventy-two studies (27,436 patients) met inclusion criteria. The mean 20-year implant survival rate was 78.9% (range: 67.2%-88.5%). Cumulative revision rate at 20 years was 21.1%. Functional outcomes showed significant improvements, with mean Harris Hip Score increasing from 43.2 preoperatively to 87.6 postoperatively. Overall complication rate was 8.6% (range: 2.3%-17.8%), with aseptic loosening (3.6%) being most common. Patient satisfaction was high (89.3%), with substantial improvements in quality-of-life measures. Ceramic-on-ceramic and ceramic-on-highly cross linked polyethylene bearings demonstrated superior long-term survival. Conclusion: THA in younger patients shows good long-term outcomes with high patient satisfaction. However, the higher revision rates compared to older populations highlight the need for careful patient selection, optimal implant choice, and managing expectations. Future research should focus on enhancing implant longevity and optimizing patient-specific approaches to further improve outcomes in this challenging population.