S
- South African Institute of Architects – Eastern Cape (SAIAEC)
- South African Institute of Architects – KwaZulu-Natal (SAIA KwaZulu-Natal)
- South African Institute of Architects – Mpumalanga (SAIAMPU)
- South African Institute of Architects (SAIA)
- South African Institute of Auctioneers (SAIA)
- South African Institute of Black Property Practitioners (SAIBPP)
- South African Institute of Building Design (SAIBD)
- South African Institute of Chartered Accountants (SAICA)
- South African Institute of Computer Scientists and Information Technologists (SAICSIT)
- South African Institute of Draughting (SAID)
- South African Institute of Draughting NPC (SAID)
- South African Institute of Electrical Engineers (SAIEE)
- South African Institute of Environmental Health (SAIEH)
- South African Institute of Financial Markets (SAIFM)
- South African Institute of Foundrymen (SAIF)
- South African Institute of Intellectual Property Law (SAIIPL)
- South African Institute of International Affairs (SAIIA)
- South African Institute of Management (SAIM)
- South African Institute of Marine Engineers and Naval Architects (SAIMENA)
- South African Institute of Materials Handling (SAIMH)
- South African Institute of Medico-Legal Experts (SAIME)
- South African Institute of Occupational Safety and Health (SAIOSH)
- South African Institute of Physics (SAIP)
- South African Institute of Professional Accountants (SAIPA)
- South African Institute of Stockbrokers (SAIS)
- South African Institute of Valuers (SAIV)
- South African International Maritime Institute (SAIMI)
- South African International Steel Fabricators (SAISF)
- South African Iron and Steel Institute (SAISI)
- South African Kabbadi Federation (SAKF)