St Paul's Anglican Church, Castle Hill, Anglican church building in Castle Hill, Australia.

St Paul's Anglican Church is a former brick church at 221 Old Northern Road, Castle Hill, south of the township near Church Street. It is a heritage-listed building that served the parish until the late 20th century. A sandstone parsonage built opposite from materials of the old St Simon's Church stands across the road.

St Simon's Church opened in the former convict barracks at Castle Hill in 1827 and closed when the new parish of St Paul was established in 1861. The parish then built a brick church at 221 Old Northern Road, south of the township near Church Street, and a sandstone parsonage opposite from materials of old St Simon's. The brick church served the parish until the late 20th century, when the congregation moved to larger premises at Rogans Hill beside Oakhill College.

The former church is where Castle Hill's Anglican parish was named for St Paul in 1861, replacing the earlier St Simon's congregation. The present parish's music ministry, CityAlight, is known for modern hymns such as "Yet Not I But Through Christ In Me", sung by a congregation of over 1,000 at Rogans Hill.

The heritage-listed former church stands at 221 Old Northern Road, south of Castle Hill township near the corner of Church Street, while the current St Paul's congregation worships at 421 Old Northern Road beside Oakhill College in Rogans Hill, about 35 km north-west of Sydney's central business district. The sandstone parsonage faces the old church across the road; both are covered by state and local preservation orders.

Materials salvaged from the original St Simon's Church were repurposed to construct a sandstone parsonage across the road from the current building. This surviving structure stands as a tangible reminder of how resources were reused when the congregation moved to its new location.