| Saint Ildefonsus | |
| Artist: | El Greco |
| Year: | 1609 |
| Medium: | oil on canvas |
| Height Metric: | 222 |
| Width Metric: | 105 |
| Museum: | Monasterio de El Escorial |
| City: | Madrid |
Saint Ildefonsus is a 1609 painting by El Greco. It and his Saint Peter were both painted for the Church of San Vicente, Toledo. It has also previously been misidentified as Pope Eugene I or saint Blaise. It is now in the Real Monasterio de San Lorenzo de El Escorial.
Ildefonsus is shown in a chasuble, pallium and mitre, holding a bishop's staff and an open book. The full robes emphasise the model's anatomy, showing Michelangelo's influence on El Greco.