"The Longest Time" is a doo-wop single by Billy Joel. The song was released as a single in 1984 as the fourth single from the 1983 album An Innocent Man. It reached number 14 on the Billboard Hot 100 and number one on Billboard's Adult Contemporary chart. In the United Kingdom the song reached number 25 on the UK Singles Chart.

The song features Joel on lead vocals and all backing vocals. Two musical instruments are present in the song: a bass guitar and a snare drum being played with brushes. When the song is covered by vocal groups, the bass part is typically sung by a human. All other sounds in the song are Joel's vocals, along with percussive sounds such as finger snaps and hand claps. Phil Ramone and Joel had intended to feature a vocal group called The Persuasions but when they sang in the studio, they tended to go flat as the song progressed. The Persuasions were dismissed and Joel recorded each of the parts himself.