Oscar dated South African model, Reeva Rebecca Steenkamp for few years. He was seen having romantic love affairs with her at the end of 2012 and early 2013. On the Valentine's Day 2013, he shot her in his home. She died in this incident. He later claimed that he was mistaken as he shot her thinking intruder hiding in the bathroom. He was sentenced to five years prison.
When Oscar was just 11 months old, he lost both of his legs. His legs were amputated below the knee. Though he didn't have both of his legs, he never felt he had no legs because of the love and care from her mother. He received his formal education from Constantia Kloof Primary School. Later he joined Pretoria Boys High School. There he was in rugby union in the school's third XV team. He also appeared in the club Olympic wrestling but after he suffered a serious knee injury in a rugby game, he began his interest in running. In 2006, he got enrolled at University of Pretoria where he majored in business management with sports science. He took part in T44 in 2004. He is one of the successful prosthetics; he was often being criticized for his artificial limbs. His net worth is said to be around $5 million.