"Illegal Alien" is a song by English rock group by Genesis. It was released as the fourth single from the album Genesis. The song reached number 41 on the charts. The song's lyrics are a lighter, humorous depiction of the frustration an illegal immigrant faces, leading up to the chorus: "It's no fun/Being an illegal alien". The song is rarely played on United States radio stations because of its perceived offensiveness toward illegal immigrants. In particular, the second stanza of the bridge — in which the trespasser offers sexual favours from his sister in exchange for admittance across the border — has been edited from radio versions of the song, as well as from the music video version.

The video uses stereotypical portrayals of Mexicans, with the participants (including Collins) shown drinking, sleeping, playing Mariachi music, wearing huge sombreros and serapes, and singing in mock-Mexican accents. The clip was filmed at the same time as the video for "Mama".