Leaving the 20th Century is a concert film of the Welsh alternative rock band Manic Street Preachers's performance at Manic Millennium, Millennium Stadium, Cardiff, Wales on New Year's Eve 1999. The concert celebrated the 10th anniversary of the band and was performed in front of more than 57,000 fans. The event became international when the final song, "A Design for Life", was broadcast live all over the world via satellite.

The concert was released on VHS and DVD on 3 July 2000 by Sony Music Video and includes interview clips in which the band discuss their history and the songs, plus an extra feature performance of "Ready for Drowning" and "If You Tolerate This Your Children Will Be Next", recorded at Château de la Motte, France in 1998.