The Silver Shell for Best Leading Performance (Spanish: Concha de Plata a la mejor interpretación protagonista; Basque: Interpretazio nagusi onenaren Zilarrezko maskorra) is one of the main awards presented at the San Sebastián International Film Festival to the Best Leading Performance of a competing film. In 2021, the San Sebastián International Film Festival announced that the two acting categories would be retired, and replaced with one gender-neutral category, with both Best Actor and Best Actress merging into the Best Leading Performance and Best Supporting Performance category.