"I Wonder Why" is a doo-wop song, written by Melvin Anderson with lyrics by Ricardo Weeks. The song was first recorded by Dion and the Belmonts.
It is sung from the point of view of a man telling his girlfriend that he loves her but does not know why. The song is noted for Carlo Mastrangelo bass part.
"I Wonder Why" was released as Laurie Records' first single, (number 3013), and was the group's first national pop chart hit, in 1958. The song went to number 22 on the Hot 100.
Nicolas Cage did a cover version of the song in the film Peggy Sue Got Married (1983).
The song was also used in the pilot episode of The Sopranos, in a scene where Tony Soprano gleefully chases Alex Mahaffey with Christopher's car through a parking lot.