- Om Sai Ram Shraddha Saburi Parivar Samiti, Sagar
- Om Sai Saamarth Parivaar Trust, Delhi
- Om Sai Shikashan Prasark Mandal, Nanded
- Om Saibahu-Uddeshiy Sanstha, Nashik
- Om Sairam Social Truest, Thiruvarur
- Om Sarvjinik Shikshan Prasarak Mandal, Aurangabad
- Om Shanti, Jabalpur
- Om Shanti, Kolkata
- Om Shivani Educational Society, Jammu
- Om Shree Om Pratisthan, Karad
- Om Shri Jai Gurudev Gramin Vikash Shodh Sansthan, Lalitpur
- Om Shri Maharudra Welfare Society, Varanasi
- Om Shri Sai Education Medical & Charitable Trust, Kachchh
- Om Shri Sai Sewa Samiti, New Delhi
- Om Siksha Samiti, Sidhi
- Om Social Society, Katni
- Om Society for Social Services, Durg
- Om Unique Seva Sansthan, Durg
- Omalur Block Women Welfare Uplift Organisation, Salem
- Omashram Trust – Old Age Care, Bangalore
- Omashram Trust Old Age Care, Bangalore
- Omega Sansthan, Allahabad
- Omegha Welfare Society, Prakasam
- Omen Welfare Society, Kota
- Omkar Charitable Trust, Satara
- Omkaram Educational Society, Udayagiri
- Omsakthi Women Development Industrial Enterprinuers Association, Chennai
- One Among U, Visakhapatnam
- One Percent Humanity, Bokaro
- One Step, Lucknow
- One World South Asia, New Delhi
- Oneness Pentecostal Christian Church Independent, Delhi
- Online Service Association, Gwalior
- Onus Society, Madhepura
- Onus Trust, Delhi
- Onward Foundation Trust, Bhavnagar
- Oodaan Good Shepherd Society, Mahasamund
- Oomang Community Center, Mumbai
- Opcar Foundation, New Delhi
- Open Educational Development Research & Welfare Society, Sangrur
- Open Forum, New Delhi
- Open Hands Rural Development Society, Vizianagaram
- Open Knowledge Society, Angamaly
- Openheart Social Organisation & Charitable Trust, Vijayawada
- OPERA, Lucknow
- Operation for Social Work Society, Sawai Madhopur
- OPK Educational & Charitable Trust, Thane
- Options, Mumbai
- Orbit Skill Foundation, Bastar
- Orbit Technologies Educational Society, Lucknow