Alan Parsons Project was the collective reference to several lineups of a British progressive rock band, active between 1975 and 1990, whose rosters consisted of Alan Parsons and Eric Woolfson surrounded by a varying number of session musicians and some relatively consistent band members such as guitarist Ian Bairnson, arranger Andrew Powell, bassist and vocalist David Paton, drummer Stuart Elliott, and vocalists Lenny Zakatek and Chris Rainbow.

Behind the revolving line-up and the regular sidemen, the true core of the Project was the duo of Parsons and Woolfson. Parsons was an audio engineer and producer by profession, but also a musician and a composer. A songwriter by profession, Woolfson was also a composer, a pianist, and a singer. Almost all songs on the Project's albums are credited to "Woolfson/Parsons".

Most of the Project's titles, especially the early work, share common traits; these were likely influenced by Pink Floyd's The Dark Side of the Moon (1973), on which Parsons was the audio engineer in 1973. They were concept albums and typically began with an instrumental introduction, which faded into the first song, often had an instrumental piece in the middle of the second LP side, and concluded with a quiet, melancholic, or powerful song. The opening instrumental was largely done away with by 1980; no later Project album except Eye in the Sky (1982) featured one, though every album includes at least one instrumental somewhere in the running order.

The group was notable for using several vocal performers instead of having a single lead vocalist. Lead vocal duties were shared by guest vocalists chosen by their vocal style to complement each song. In later years, Woolfson sang lead on many of the group's hits.

Although the vocalists varied, a small number of musicians worked with the Alan Parsons Project regularly. These core musicians contributed to the recognisable style of a Project song in spite of the varied singer line-up.