2006 – Humboldt State left the GNAC to join the California Collegiate Athletic Association (CCAA) 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 (NCC) and Western Oregon competing as a D-II Independent.
2008 – Dixie State University (now Utah Tech University) joined the GNAC as an affiliate member for football (with Humboldt State returning for that sport) with the 2008 fall season (2008–09 academic year), leading to the GNAC to begin sponsoring football once again.
2010 – Simon Fraser University joined the GNAC in the 2010–11 academic year, becoming the first Canadian institution of higher education.
2012 – Three institutions joined the GNAC as affiliate members, all effective in the 2012 fall season (2012–13 academic year):
2013 – South Dakota School of Mines and Technology (South Dakota Mines) joined the GNAC as an affiliate member for men's soccer in the 2013 fall season (2013–14 academic year).
2014 – South Dakota Mines added football to its GNAC affiliate membership in the 2014 fall season (2014–15 academic year).
2015 – South Dakota Mines left the GNAC as an affiliate member for men's soccer after the 2014 fall season (2014–15 academic year).
2016 – Dixie State and South Dakota Mines left the GNAC as affiliate members for football 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 in the 2020 spring season (2019–20 academic year).
2020 – Concordia–Portland left the GNAC as the school ceased operations 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 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 after the 2021 fall season (2021–22 academic year), bringing an end to the GNAC as a football conference for a second time.
^Represents the calendar year when fall sports competition begins.
^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) Associate member (sport)
The GNAC did not sponsor football during the 2006 and 2007 fall seasons (2006–07 and 2007–08 school years). Therefore, Central Washington and Western Washington competed in the North Central Conference (NCC); while Dixie State, Humboldt State and Western Oregon competed as 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.