The 1991 San Francisco State Gators football team represented San Francisco State University during the 1991 NCAA Division II football season. San Francisco State competed in the Northern California Athletic Conference (NCAC). The Gators were led by first-year head coach Harold Hamilton. Hamilton was the third Gator head coach in three years. They played home games at Cox Stadium in San Francisco, California. The team finished the season with a record of four wins and seven losses (3–7, 2–3 NCAC). For the season the team was outscored by its opponents 257–288.