- IAS
- see International AIDS Society (1988 - ) - IASC
- see Inter-Agency Standing Committee (1992 - ) - ICASO
- see International Council of AIDS Service Organizations (1991 - ) - ICG
- see International Crisis Group (1995 - ) - ICW
- see International Community of Women Living with HIV/AIDS (1992 - ) - IEC
- see Communications programming - IEC
- see Health education - IFAD
- see International Fund for Agricultural Development (1977 - ), United Nations - IFRC
- see International Red Cross and Red Crescent Societies (1919 - ) - IGCAHRD
- see Intergovernmental Committee on HIV/AIDS, Hepatitis C and Related Diseases (1987 - ), Australian Government - Illicit drugs
- see Injecting drug use - ILO
- see International Labour Organization (1919 - ), United Nations - IMF
- see International Monetary Fund - Independent State of Papua New Guinea, Papua New Guinea
- Independent State of Samoa, Samoa
- India, Republic of India
- India, Republic of, National AIDS Control Organisation (1992 - )
- Indian Council of Medical Research, National AIDS Research Institute (1992 - )
- Indian Network for People Living with HIV/AIDS (1997 - )
- Indigenous people and minorities
- Indonesia, Republic of Indonesia
- Indonesia, Republic of, National AIDS Commission (1994 - )
- Information
- see Communications programming - Information, education and communication materials
- see Communications programming - Information, education and communication materials
- see Health education - Injecting drug use
- INP+
- see Indian Network for People Living with HIV/AIDS (1997 - ) - Institute of Social Development Studies
- Intellectual property
- Inter-Agency Standing Committee (1992 - )
- Intergovernmental Committee on HIV/AIDS, Hepatitis C and Related Diseases (1987 - ), Australian Government
- International AIDS Society (1988 - )
- International Center for Research on Women (1976 - )
- International Community of Women Living with HIV/AIDS (1992 - )
- International Council of AIDS Service Organizations (1991 - )
- International Crisis Group (1995 - )
- International Fund for Agricultural Development (1977 - ), United Nations
- International HIV/AIDS Alliance (1993 - )
- International Labour Organization (1919 - ), United Nations
- International Monetary Fund
- International Organization for Migration (1951 - )
- International Planned Parenthood Federation (1952 - )
- International Red Cross and Red Crescent Societies (1919 - )
- International Save the Children Alliance (1997 - )
- International Strategy for Disaster Reduction (1999 - ), United Nations
- Intimate partner transmission
- see Sex workers and clients - Intimate partner transmission
- see Sexual and reproductive health - IOM
- see International Organization for Migration (1951 - ) - IP
- see Intellectual property - IPPF
- see International Planned Parenthood Federation (1952 - ) - ISDR
- see International Strategy for Disaster Reduction (1999 - ), United Nations - ISDS
- see Institute of Social Development Studies - The Islamic Republic of Afghanistan, Afghanistan
- Islamic Republic of Pakistan, Pakistan