"What Is This Thing Called Love?" is a song written by Jimmy Jam and Terry Lewis and recorded by American recording artist Alexander O'Neal. It is the second single from the singer's fourth solo album, All True Man (1991). The song's distinctive backing vocals were performed by Lisa Keith. Following the successful chart performances of the All True Man single "All True Man", "What Is This Thing Called Love?" was released as the album's second single.

All True Man is the fourth studio album by American recording artist Alexander O'Neal. The album was a success in the UK, peaking at number two, though sales did not reach the levels of his previous album, Hearsay.