"What a Fool Believes" is a song written by Michael McDonald and Kenny Loggins and first recorded and released by Loggins on his 1978 album Nightwatch. The best-known version was recorded by the American rock band the Doobie Brothers for their eighth album Minute by Minute (1978). Debuting at number 73 on January 20, 1979, the single reached number 1 on the Billboard Hot 100 on April 14, 1979, for one week. The song received Grammy Awards in 1980 for both Song of the Year and Record of the Year. In 2024, the song was inducted into the Grammy Hall of Fame.