The 1978 Washington State Cougars football team was an American football team that represented Washington State University in the Pacific-10 Conference (Pac-10) during the 1978 NCAA Division I-A football season. Under new head coach Jim Walden, the Cougars compiled a 4–6–1 record (2–6 in Pac-10, last), and were outscored 296 to 276. The team's statistical leaders included Jack Thompson with 2,333 passing yards, Tali Ena with 728 rushing yards, and Mike Wilson with 451 receiving yards.