Fox, who served as president of Mexico from 2000 to 2006, is giving the keynote speech Saturday at the annual International Cannabis and Hemp Expo at Civic Center Plaza.
He will then give another speech at a small private dinner at another location that evening, said Lilia Ledezma, a consultant for the event organizers.
Fox plans to discuss the need for peaceful solutions to the war against drug cartels along the border between the U.S. and Mexico.
Ledezma said the former president has expressed support for the legalization of marijuana as a way to combat the violent cartels.
The cannabis expo starts at 10 a.m. Saturday in the outdoor plaza near City Hall. State Assemblyman Tom Ammiano and San Francisco Supervisors David Campos and Scott Wiener are other scheduled speakers at the event.
More information about the expo can be found online at www.intche.net/sept-7-2013-san-francisco.