Founded in 1926, Alpha Gamma Sigma was the first community college honor society in California. The organization promotes scholarship, service and fellowship and is recognized by universities, businesses and organizations everywhere.

The motto of AGS, "Add to good knowledge, character, and judgement," was adopted in 1932. The three Greek words Arete, Gnosis, and Sophrosyne were chosen as the embodiment of the motto. These were then shortened to Alpha Gamma Sigma.

The Gamma Eta Chapter at Los Angeles Mission College was formed in the mid 1990s by Professor of English John Orozco. Orozco remained faculty advisor for the Gamma Eta chapter up until 1999, when he handed control to Professor of Philosophy Mark Pursley. The chapter is currently advised by Professor of English Ruthie Grant, who has been advisor since 2003.

The mission of this chapter and organization shall be to foster, promote, maintain, and recognize scholarship among students at Los Angeles Mission College; to develop programs offering cultural, social, and enrichment activities as part of the total college experience; to promote service to the college, the community, and the Gamma Eta Chapter; and to emphasize the development of leadership, character, and judgment.

Meetings are held every Tuesday at 2:00 PM in room 5 of the Campus Center (highlighted in gold), and at 6:00 PM in the ASO Conference Room, downstairs in the Campus Center (highlighted in green).