Simone Biles is the most decorated gymnast ever, with a total of 34 medals across the world championships and Olympics, making her the most decorated gymnast ever - male or female - at the sports two signature events. She has won 27 world championship medals, including 21 golds, and six individual all-around titles. It is worth noting that the question did not specify whether it referred to Olympic medals or all medals, but Simone Biles holds the record for both.