The decisive body of the IOF is the members in General Assembly. A General Assembly may be either Ordinary or Extraordinary. The Ordinary General Assembly shall meet biennially. Each IOF member has the right to send three delegates to a General Assembly. Each member represented at the General Assembly, except for provisional members, has one vote.
The next IOF Ordinary General Assembly will take place in July 2020, in connection with the World Orienteering Championships in Denmark.
Since the IOF was founded in 1961, the IOF Congress and General Assembly has been held as follows:
| No. | Year | Venue |
| 1 | 1961 | Copenhagen, DEN |
| 2 | 1963 | Leipzig, GDR |
| 3 | 1965 | Kamtschia, BUL |
| 4 | 1967 | Mooserboden, AUT |
| 5 | 1969 | Budapest, HUN |
| 6 | 1971 | Kiljava, FIN |
| 7 | 1973 | Magglingen, SUI |
| 8 | 1975 | Bosön-Stockholm, SWE |
| 9 | 1977 | Innsbruck, AUT |
| 10 | 1980 | Malente, FRG |
| 11 | 1982 | Liége, BEL |
| 12 | 1984 | Maynooth, IRL |
| 13 | 1986 | Ry, DEN |
| 14 | 1988 | Torbole, ITA |
| 15 | 1990 | Cambridge, GBR |
| 16 | 1992 | Filzbach, SUI |
| 17 | 1994 | Varna, BUL |
| 18 | 1996 | Jerusalem, ISR |
| 19 | 1998 | Sintra, POR (ordinary General Assembly) and *Extraordinary General Assembly |
| 20 | 2000 | Graz, AUT |
| 2001 | Tampere, FIN** |
|
| 21 | 2002 | Fontainebleau, FRA |
| 22 | 2004 | Västerås, SWE (ordinary General Assembly) and *Extraordinary General Assembly |
| 23 | 2006 | Aarhus, DEN |
| 24 | 2008 | Prostejov, CZE |
| 25 | 2010 | Trondheim, NOR |
| 26 | 2012 | Lausanne, SUI |
| 27 | 2014 | Lavarone, ITA |
| 2015 | Inverness, GBR ** | |
| 28 | 2016 | Strömstad, SWE |
| 29 | 2018 | Prague, CZE |
| 30 | 2020 | Online conference |
| 2022 | Online conference *** | |
| 31 | 2022 | Triangle Region, DEN |
*An Extraordinary General Assembly was held in conjunction with the Ordinary General Assembly.
**An Extraordinary General Assembly held in conjunction with the Presidents’ Conference.
***An Extraordinary General Assembly was held on March 25 with statutes amendments as the only order of business.