The 1978 Cal Poly Mustangs football team represented California Polytechnic State University, San Luis Obispo as a member of the California Collegiate Athletic Association (CCAA) during the 1978 NCAA Division II football season.
Led by 11th-year head coach Joe Harper, Cal Poly compiled an overall record of 7–3 with a mark of 2–0 in conference play, winning the CCAA title for the third consecutive season.
The conference title was unofficial as the CCAA had only three members.
[1] The Mustangs advanced to the NCAA Division II Football Championship playoffs for the first time, where they lost to Winston-Salem State in the quarterfinals.
Cal Poly played home games at Mustang Stadium in San Luis Obispo, California.