"Jealousy" is a song originally written in 1982 by English synth-pop duo Pet Shop Boys, recorded for their fourth studio album, Behaviour (1990).

[6] In 1982, Chris Lowe composed the melody at the piano in his parents' home and, as he felt it should be a ballad, asked Tennant to write an intense-sounding lyric.

[1][7] Tennant complied by writing about the simplest form of jealousy: infidelity suspicions aroused by someone's indifferent or disrespectful attitudes towards another person's feelings (such as making his/her partner wait all night for a phone call which never comes).

The extended version of the single version lengthens the outro while adding an orchestral intro as well; in addition, Neil Tennant recites a quote from William Shakespeare's Othello (Act III, Scene III) over both sequences:[7][1]Not poppy, nor mandragora, Nor all the drowsy syrups of the world, Shall ever medicine thee to that sweet sleep Which thou owedst yesterday.

"Jealousy" is also one of the songs covered on Goes Petshopping, the debut album by Pet Shop Boys tribute band West End Girls.

[12] "Losing My Mind", taken from the Stephen Sondheim musical Follies, was based on a demo originally recorded for the Liza Minnelli album Results.