A Long Day's Night is a live album by American hard rock band Blue Öyster Cult, recorded in Chicago, Illinois, on 21 June 2002. The title is a reference to the album being recorded during the summer solstice, the longest day of the year.

The concert was released as a DVD and a CD; the CD does not include seven of the songs included on the DVD-release ("E.T.I.," "Harvester of Eyes," "Flaming Telepaths," "Then Came the Last Days of May," "ME 262" and the encore songs "Dominance and Submission" and "The Red and the Black"), while the CD-release featured "Astronomy", not available on the DVD.

In 2004, 10 tracks from this concert were released again as Extended Versions: The Encore Collection.