Hetty Balkenende is a Dutch former freestyle swimmer and synchronized swimmer who won a silver medal in the 4×100 m freestyle relay at the 1954 European Aquatics Championships. In 1955, she helped the Dutch team set the world record in the same event; she also won two national titles, broke two national records in the 400 m freestyle, and the world record over 880 yards – all in one year. She was selected for the Dutch Olympic team, but the Netherlands boycotted the 1956 Summer Olympics in protest over the Soviet handling of the Hungarian uprising, so Balkenende missed the opportunity to acquire an Olympic medal.