- Independent Producers Organisation (IPO)
- Independent Regulatory Board for Auditors (IRBA)
- Independent Schools Association of South Africa (ISASA)
- Independent South African National Civic Organisation (ISANCO)
- Indian Academy of South Africa (IASA)
- Indoor Cricket Association (ICA)
- Industrial Development Corporation of South Africa (IDC)
- Information Systems Audit and Control Association South Africa Chapter NPC (ISACA-SA)
- Information Technology Association of South Africa (ITA)
- Information Technology Users Council (ITUC)
- Inhlangano Yabelaphi Ngenkolo Nangokomoya (IYNN)
- Inkatha Freedom Party (IFP)
- Innovation for The Blind (IFB)
- Innovative Pharmaceutical Association South Africa (IPASA)
- Institute for African Alternatives (IFAA)
- Institute for Aviation Medicine (IAM)
- Institute for Commercial Forestry Research (ICFR)
- Institute for Futures Research (IFR)
- Institute for Global Dialogue (IGD)
- Institute for Landscape Architecture in South Africa (ILASA)
- Institute for Local Government Management (ILGM)
- Institute for Municipal Administrators of Southern Africa (IMASA)
- Institute for Municipal Public Safety of Southern Africa (IMPS-SA)
- Institute for Occupational Therapists In Private Practice (INSTOPP)
- Institute for Practicing Statisticians (ICCSSA)
