St John's Seminary, Wonersh

St John's Seminary was a Roman Catholic seminary established in 1891 and located at Wonersh near Guildford in Surrey, in the Diocese of Arundel and Brighton, United Kingdom. St John's was the principal seminary for that diocese and also for the Archdiocese of Southwark, and for other dioceses to a greater or lesser extent, including Plymouth, Portsmouth, East Anglia, Clifton, Menevia, and also for the Archdiocese of Cardiff and the newly-founded Ordinariate of Our Lady of Walsingham.

In late 2020 it was announced that the seminary would close. The seminary was in continuous use until the building was officially vacated in December 2022 after all sacred objects and articles had been removed and re-homed in Catholic churches and institutions in the UK and beyond.

The seminary served mainly the dioceses of the South of England; it also provided formation for students from dioceses further afield and for members of religious institutes. From 1985 it offered courses in theology for lay (external) students. These courses ran alongside the academic programme offered to students in formation. This programme was validated by St Mary's University, Twickenham, of which the seminary was an Associated Institution. The seminary was also a resource for local Church activities, and provided a venue for various groups including the formation programme for the Permanent Diaconate, as well as a centre of expertise in the work of formation and sacred science.

The seminary occupied a building listed Grade II on the National Heritage List for England.