- Oak Tree Tenants and Residents Association (OTTRA)
- Odyssians
- Office of the Police and Crime Commissioner for Thames Valley
- Open Doors UK
- Open Hand Open Space
- Organisation for Sickle Cell Anaemia Reading (OSCAR)
- Orts Road Housing Co-operative
- Our Friendship Club
- Outrider Anthems
- Over 50s Community Activity Cafe
- Oxfam (London)
- Oxfam Books and Music Shop
- Oxfam Bookshop (Reading)
- Oxfam Music Shop (Reading)
- Oxfam Shop (Caversham)
- Oxfam Shop (Pangbourne)
- Oxford Diocesan Council for the Deaf (ODCD)
- Oxford Diocesan Council for the Deaf and Hard of Hearing (ODCD)
- Oxford Road Community Garden (ORCG)
- Oxford Road Safer Neighbourhood Forum (SNF)
- Oxford Road Scout Group
- Oxjam Reading Takeover
