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- 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)
- Institute for Security Studies (ISS)
- Institute for Soil, Climate and Water (ARC-ISCW)
- Institute for Sport Research (ISR)
- Institute for Technological Innovation (ITI)
- Institute for The Advancement of Journalism (IAJ)
- Institute for The Study of Englishes In Africa (ISEA)
- Institute for Timber Construction South Africa (ITC-SA)
- Institute for Tropical and Subtropical Crops (ARC-ITSC)
- Institute for Water Research (IWR)
- Institute for Work at Height (IWH)
- Institute of Accounting and Commerce (IAC)
- Institute of Accounting and Commerce of South Africa (IACSA)
- Institute of Bankers in South Africa (IOBSA)
- Institute of Brewing and Distilling (IBD)
- Institute of Business Administration In South Africa (IBM)
- Institute of Business Advisers Southern Africa (IBASA)
- Institute of Certificated and Chartered Statisticians of South Africa (ICCSSA)
- Institute of Certified Bookkeepers (ICB)
- Institute of Certified Mechanical and Electrical Engineers, South Africa (ICMEESA)
- Institute of Chartered IT Professionals (ICITP)
- Institute of Chartered Shipbrokers, South Africa (ICSSA)
- Institute of Commercial Forensic Practitioners (ICFP)
- Institute of Credit Management of South Africa (ICM)
- Institute of Directors South Africa (IoDSA)