"Believe It or Not" is a song composed by Mike Post (music) and Stephen Geyer (lyrics) and sung by American singer Joey Scarbury. It serves as the theme song for the television series The Greatest American Hero. The track was later included on Scarbury's 1981 debut album America's Greatest Hero.

 

The theme song became a popular hit during the run of The Greatest American Hero. "Believe It or Not" debuted in the Top 40 of the Billboard Hot 100 on June 13, 1981, eventually peaking at number 2 during the weeks ending August 15–22, 1981, kept off the top spot by "Endless Love" by Diana Ross and Lionel Richie, and spending a total of 18 weeks in the Top 40. It also peaked at the number 1 position on the Record World Chart.