Genu valgum is a well-documented deformity secondary to hereditary multiple exostoses about the knee. Post-traumatic tibia valgus is also a well-described phenomenon that occurs in children who sustain an incomplete fracture of the proximal tibia. The finding is considered to be secondary to asymmetric blood flow to the proximal tibial physis. The existing literature only describes genu valgum as a sequela of the hereditary multiple exostoses disorder itself and does not address genu valgum occurring as a postoperative consequence of mass excision. In this paper, we report on three pediatric patients who developed unilateral genu valgum after removal of osteochondromas from the medial proximal tibia. Chart and radiographic data were retrospectively reviewed for a series of three patients. Three patients developed genu valgum after medial proximal tibial osteochondroma excision. The maximum tibiofemoral angle varied from 17 to 23°. One case resolved spontaneously with observation, one was addressed surgically with guided growth correction, and another was advised to undergo operative correction, but declined. We conclude that genu valgum can arise secondary to osteochondroma excision when the mass is resected near the proximal tibial physis. Surgeons should counsel patients on the possibility of postoperative angular growth deformity and monitor closely for its development.