The 1999 Backlash was a professional wrestling pay-per-view (PPV) event produced by the World Wrestling Federation (WWF; WWE as of 2002). It was the inaugural Backlash and took place on April 25, 1999, at the Providence Civic Center in Providence, Rhode Island and was presented by Castrol GTX. The event had originally been promoted as "Backlash: In Your House", but the branding was dropped as the WWF discontinued the In Your House series before Backlash was held. As a result, Backlash was the first non-In Your House monthly PPV held by the promotion outside of their five major events at the time (the In Your House branding would be revived by WWE for its NXT developmental brand in 2020). The concept of the pay-per-view was based around the backlash from WWF's flagship event, WrestleMania.

In line with the event's concept, the main event was a rematch from WrestleMania XV between Stone Cold Steve Austin and The Rock for the WWF Championship, but this time with a special guest referee, Shane McMahon. Lower down on the card, Big Show and Mankind had a Boiler Room Brawl to settle matters after their previous encounter, which decided who would referee the WrestleMania event. Triple H also wrestled X-Pac due to Triple H causing X-Pac to lose a match for the European Championship the previous month.