1940 Cal Poly Mustangs football team

The 1940 Cal Poly Mustangs football team represented California Polytechnic School—now known as California Polytechnic State University, San Luis Obispo—as an independent during the 1940 college football season. Led by eighth-year head coach Howie O'Daniels, Cal Poly compiled a record of 6–3. The team outscored its opponents 148 to 83 for the season.

Cal Poly was ranked at No. 391 (out of 697 college football teams) in the final rankings under the Litkenhous Difference by Score system for 1940.

The Mustangs played home games at Mustang Stadium in San Luis Obispo, California.

Cal Poly was a two-year school until 1941 and competed as an independent from 1929 to 1945.