-
- Oak street, green street baptist: manchester city centre
- Oak Street- See Manchester, Cooper Street Calvinistic Methodist (above): Manchester City Centre
- Octagon calvinistic methodist: chester
- Octagon unitarian, temple court: liverpool
- Ogden baptist: butterworth (rochdale)
- Ogden Street Primitive Methodist- See Ardwick, Higher Ardwick Primitive Methodist (above): Ardwick
- Old chapel presbyterian: dukinfield
- Old glossop wesleyan, wesley street: glossop
- Old Market Street Wesleyan- See Blackley, Exchange Street Wesleyan (above): Blackley
- Old st george: stalybridge
- Oldham road congregational: manchester city centre
- Oldham road primitive methodist: royton
- Oldham Road Wesleyan- See Manchester, Wesley, Livesey Street, Oldham Road (below): Manchester City Centre
- Oldham street methodist new connexion: manchester city centre
- Oldham Street Wesleyan- See Manchester, Central Hall, Oldham Street (formerly Oldham Street Wesleyan) (above): Manchester City Centre
- Orchard street independent: stockport
- Ordsall Park Wesleyan- See Salford, Dock Methodist Mission (above): Salford
- Our Lady and St John (Roman Catholic): Chorlton-on-Medlock
- Our Lady and St Nicholas- See Liverpool, St Nicholas (below): Liverpool
- Our lady of mercy and st thomas of canterbury: gorton