The county of West Sussex in South East England has 176 Grade I listed buildings. Such buildings are described by English Heritage, the authority responsible for their designation, as "of exceptional interest [and] sometimes considered to be internationally important". Grade I is the highest of the three grades of listed status in England: about 2.5% of the country's 374,000 listed buildings have this designation.

The Cathedral Church of Our Lady and St Philip Howard is located in Arundel, West Sussex, England. Dedicated in 1873 as the Catholic parish church of Arundel, it became a cathedral at the foundation of the Diocese of Arundel and Brighton in 1965. It now serves as the seat of the Bishop of Arundel and Brighton.