Jopie Troost was a Dutch competitive swimmer who was active during the 1950s and 1960s. Troost represented the Hollandse Dames Zwemclub in Amsterdam when she was called up to compete for the national at the 1958 European Championships. A mainstay in the 4 × 100 m freestyle relay team, she was part of the quartet that broke the Dutch record on three occasions during the same year. In 1960 she swam in the relay at the Roma Olympics, but the Dutch team were disqualified in their heat when Sieta Posthumus dived into the water before Troost had made the touch.