Background: The purpose of this study was to evaluate return to sports (RTS) after opening wedge high tibial osteotomy (OWHTO) in elderly patients and associated factors affecting RTS.Methods: Seventy-four patients (mean age 68 years) who underwent OWHTO were enrolled. Clinical outcomes were evaluated using the Knee Society Score (KSS). Patients were asked regarding types of sports activities and their levels of participation within preoperative 1 year and postoperative 1 year. Levels of participation in sports and recreational activities were examined using the Tegner activity scale. The outcomes were compared between two age groups (≥70 years vs <70 years).Results: Of the 74 patients overall, 59 participated in at least one sport preoperatively, and 55 returned to sports postoperatively (RTS 93%). The KSS knee score and function score were significantly improved after surgery in both age groups (P<0.05), but no significant differences were found between the age groups. The Tegner activity scales for ≥70 years and <70 years were 2.9±1.1 and 4.0±1.9 preoperatively (P<0.01) and 2.7±1.2 and 3.3±1.4 postoperatively (P=0.16), respectively. RTS was reported by 24 of 25 (96.0%) in the age <70 years group and 31 of 34 (91.2%) in the age ≥70 years group. Of the patients who reported RTS, 66.7% in the age <70 years group and 77.4% in the age ≥70 years group could return to the same or higher level.Conclusions: The rate of RTS after OWHTO was high in elderly patients. OWHTO is a preferred surgical option for elderly patients who desire RTS.