Continuity mistake: When Lucas is with Keith at the graveyard in 4-10 and Brooke is standing in front of "Peyton's" tombstone, it says she died on March 1, 2006. Keith notes that she died on the day of the shooting. However in this episode Lucas visits Keith's grave where his tombstone says he died in January 2016.
Prom Night at Hater High - S4-E15
Continuity mistake: In this episode a sex tape shows a fling between Brooke and Nathan, and it is supposed to be from the past, but Nathan's hair is much longer and so obviously older in the video that it looks like it could have been filmed the night before, not from when he and Peyton were together.
All of a Sudden I Miss Everyone - S4-E21
Continuity mistake: When all of the girls dance to the Spice Girls song "If You Wanna Be My Lover", during this scene Haley's shoes repeatedly change from high heels to trainers whilst she is dancing.
