| Building Name: | Saint John's Tower |
| Native Name: | Túr Naomh Sheáin |
| Native Name Lang: | ga |
| Map Type: | Ireland Castledermot#Ireland |
| Location: | Skenagun, Castledermot, County Kildare, Ireland |
| Coordinates: | 52.914°N -6.8378°W |
| Religious Affiliation: | Catholic |
| Heritage Designation: | National Monument |
| Architecture Style: | Norman |
| Founded By: | Walter de Riddlesford |
| Groundbreaking: | 1210 |
| Height Max: | 10 m (30 ft) |
| Materials: | Stone |
Saint John's Tower, also called the Pigeon Tower,[1] is a tower in Castledermot, County Kildare, Ireland. A former bell tower, it is all that remains of a medieval leper hospital and is a National Monument.
Saint John's Tower is located on the northern end of the Main Street, Castledermot.
The Priory and Hospital of St John the Baptist was founded by Walter de Riddlesford and his wife in 1210, just outside the Dublin gate of the walled town of Castledermot. It was occupied by the Crutched Friars (Fratres Cruciferi) until its dissolution in 1541.[2]