Breakdown: In Your House was the 24th In Your House professional wrestling pay-per-view (PPV) event produced by the World Wrestling Federation (WWF; WWE as of 2002). It took place on September 27, 1998, at the Copps Coliseum in Hamilton, Ontario, Canada. Nine matches were held on the PPV, while three matches were held for the Sunday Night Heat pre-show. The promotional poster featured D-Generation X, whose entrance theme was titled "Break It Down." The event is notable for featuring the debut of Christian.

The main event was a Triple Threat match between Stone Cold Steve Austin, The Undertaker, and Kane for the WWF Championship, which ended in controversy when The Undertaker and Kane simultaneously pinned Austin. Another match at the event was a Triple Threat match in a steel cage between Ken Shamrock, Mankind, and The Rock to determine the number-one contender to the WWF Championship.