Factors influencing the clinical outcomes after periacetabular osteotomy (PAO) have not been well explored. This study evaluated the influence of symptom duration in developmental dysplasia of the hip on short-term patient-reported outcomes after PAO. A retrospective review of prospectively collected data identified PAOs performed on 139 patients. Sixty-five patients were then stratified into two groups based on preoperative symptom duration: 2 years or less (n=22) vs more than 2 years (n=43). We compared the results of hip-specific patient-reported outcome surveys collected preoperatively and postoperatively. When comparing the two groups, we found no significant differences in clinical outcome scores except for the UCLA Activity Scale. The shorter duration group achieved improvement 6 months postoperatively on the visual analog scale average pain score (from 4.5 to 2.167; P=.0017), International Hip Outcome Tool-12 (from 42.95 to 59.19; P=.0176), and Harris Hip Score (from 53.88 to 69.88; P=.049). The longer duration group also achieved postoperative improvement across multiple surveys. Nevertheless, a multivariate analysis controlling for age, sex, and body mass index and found that symptom duration did not independently affect the change in clinical outcomes. Although PAO leads to improvements in functional status and pain, preoperative symptom duration does not significantly affect these clinical outcomes. [Orthopedics. 2023;46(6):365-372.].