The 1965 Oklahoma State Cowboys football team represented Oklahoma State University–Stillwater in the Big Eight Conference during the 1965 NCAA University Division football season. In their third season under head coach Phil Cutchin, the Cowboys compiled a 3–7 record (2–5 against conference opponents), tied for fifth place in the conference, and were outscored by opponents by a combined total of 173 to 131. Running back Walt Garrison and guard Charles Harper were selected as a first-team All-Big Eight Conference player. The team played its home games at Lewis Field in Stillwater, Oklahoma.