2006 - Humboldt State left the GNAC to join the California Collegiate Athletic Association (CCAA), effective after the 2005-06 academic year. This would result in the GNAC dropping football, with Western Washington and Central Washington becoming football affiliates of the now defunct North Central Conference and Western Oregon competing as a D-II independent.
2008 - Dixie State University joined the GNAC as an affiliate member for football (with Humboldt State returning for that sport), effective with the 2008 fall season (2008-09 academic year), leading to the GNAC to begin sponsoring football once again.
2013 - South Dakota School of Mines and Technology (South Dakota Mines) joined the GNAC as an affiliate member for men's soccer, effective in the 2013 fall season (2013-14 academic year).
2014 - South Dakota Mines added football to its GNAC affiliate membership, effective in the 2014 fall season (2014-15 academic year).
2015 - South Dakota Mines left the GNAC as an affiliate member for men's soccer, effective after the 2014 fall season (2014-15 academic year).
2016 - Dixie State and South Dakota Mines left the GNAC as affiliate members for football, effective after the 2015 fall season (2015-16 academic year).
2019 - Humboldt State left the GNAC as an affiliate member for football as the school announced it was dropping the sport after the 2018 fall season (2018-19 academic year).
2019 - The University of California San Diego (UC San Diego) and the University of Central Oklahoma (along with Humboldt State returning for that sport), joined the GNAC as affiliate members for women's rowing, effective in the 2020 spring season (2019-20 academic year).
2020 - Concordia–Portland left the GNAC as the school announced that it would close, effective after the 2019-20 academic year.
2020 - Azusa Pacific left the GNAC as an affiliate member for football as the school announced it was dropping the sport after the 2020 fall season (2020-21 academic year).
2020 - UC San Diego left the GNAC as an affiliate member for women's rowing, effective after the 2020 spring season (2019-20 academic year), coinciding with the start of its transition to NCAA Division I.
2022 - Central Washington, Western Oregon and Simon Fraser, the only 3 football-sponsoring schools remaining in the GNAC, announce that they will be joining the Lone Star Conference as football affiliates, bringing an end to the GNAC as a football conference for a second time, effective after the 2021 fall season (2021-22 academic year).
^Cal Poly Humboldt was a full member of the GNAC from 2001–02 to 2005–06, and was as an affiliate member of the GNAC for football from the 2008 to 2018 fall seasons (2008–09 to 2018–19 school years).
^Formerly known as Humboldt State University until January 26, 2022.
Full member (all sports) Full member (non-football) Associate member (football-only) Associate member (other sports)
The GNAC did not sponsor football in the 2006–07 and 2007-08 seasons. Therefore, Central Washington and Western Washington competed in the North Central Conference (NCC); while Dixie State, Humboldt State and Western Oregon were Independents.
^ abcdDe facto Division I sport. The NCAA holds a combined national championship event in men's ice hockey open to both Division I and Division II members, and single championship events open to members of all three divisions in women's gymnastics and the coeducational sports of rifle and skiing.