Social and political groups and parties, state, commerical and civil institutions.
- Identity Magazine
- Industrial Relations Commission
- Industrial Workers of the World (1905 - )
- Industrial Workers of the World (c. 1980 - )
- International - organ of the Australian Section of the Fourth International (1960 - 1976)
- International Bookshop
- International Socialist Club (1898 - )
- International Socialist Congress
- International Socialist Organisation
- International Socialist Party
- International Socialists (1975 - )
- IWW
- see Industrial Workers of the World (1905 - ) - IWW
- see Industrial Workers of the World (c. 1980 - )