"Shouldn't Be" (Chinese: 不該; Bù Gāi) is a song by Taiwanese recording artists Jay Chou and A-Mei.

Its production utilizes instrumentations of the piano, violin, and drums, while its lyrical content discusses pain associated with lost love and the separation of lovers.

The song received positive reviews from music critics, who praised the vocal performance of both singers as well as the production of the track.

An accompanying music video for "Shouldn't Be" features actor Edison Huang cloning himself in an attempt to remain with his lover, while Chou and A-Mei sing the track amid a futuristic set.

Jay Chou and A-Mei have previously expressed interest in working with each other for years, as both artists have crossed paths numerous times at different concerts and events.