Data on return to work and sport following open wedge high tibial osteotomy (HTO) have been underreported. Furthermore, there is no clear consensus in literature about the postoperative alignment goals following HTO. A retrospective case series was performed to evaluate return to sport and work following open wedge HTO. The University of California, Los Angeles scale, the German classification system according to the Reichsausschuß für Arbeitszeitermittlung, the Tegner score and the Knee injury and Osteoarthritis Outcome Score were used to asses the employment status, sport status and clinical outcome at the time of surgery and at final follow-up, minimum 2 years after surgery. The pre- and postoperative hip knee ankle angle (HKA) were documented. The desired postoperative alignment target was 0°-2° valgus mechanical axis. 30 open wedge HTOs were performed of which 27 patients were retrospectively included in the study. 25 out of 26 patients returned to work and 15 out of 17 patients returned to sport following surgery. Outcome scores were significantly higher after surgery. The mean postoperative HKA was 0,9° of valgus mechanical axis. This study shows excellent outcome in sport and work activity and clinical outcome after open wedge HTO. We furthermore suggest that these outcomes can be obtained with a postoperative alignment of 0°-2° of valgus mechanical axis.