The 1991 UC Davis football team represented the University of California, Davis as a member of the Northern California Athletic Conference (NCAC) during the 1991 NCAA Division II football season.
Led by third-year head coach Bob Foster, the Aggies compiled an overall record of 7–3 with a mark of 3–2 in conference play, placing second in the NCAC.
UC Davis' loss to Chico State on October 29 broke a streak of 52 consecutive conference wins that started in the 1981 season.
And it ended a remarkable string of 90 conference wins in 91 games stretching back to the 1981 season.
The Aggies played home games at Toomey Field in Davis, California.