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

Wonersh is a village and civil parish in the Waverley district of Surrey, England and Surrey Hills Area of Outstanding Natural Beauty. Wonersh contains three Conservation Areas and spans an area three to six miles SSE of Guildford.