The movie The Wizard of Oz, made in 1939, in mentioned several times in Buffy the Vampire Slayer:
Buffy refers to the hyena-possessed bullies in The Pack as the “winged monkeys”. The phrase comes from the scene in The Wizard of Oz in which the Wicked Witch of the West sends her loyal winged monkeys to collect Dorothy and the ruby slippers. In Flooded, Andrew says he trained flying demon monkeys to disrupt the school play.
In Nightmares, Billy Palmer awakens from his coma and, seeing the Scoobies around his bed, says, “I had the strangest dream. And you were in it, and you”. This is a reference to when Dorothy wakes in her bed and sees her friends around her.
In What’s My Line? (Part 2), Xander says, “Welcome my little pretties”. In The Wizard of Oz, the Wicked Witch of the West called Dorothy her “pretty”.
In The Yoko Factor, Willow says, “If ever a whiz there was.” This is a line from the song in the film ‘Follow the Yellow Brick Road’ / ‘We’re Off To See the Wizard’.
The episode No Place Like Home takes it’s name from Dorothy clicking her heels together and repeating the phrase, “There’s no place like home” in order to get back to her Kansas home. A similar reference to this phrase is in the Angel episode There’s No Place Like Plrtz Glrb.
In Grave, Willow says, “Fly my pretty…fly!” when she sends her ball of fire to find Andrew and Jonathan. This is what the wicked witch says to her flying monkeys when she sends them off. In Empty Places, Rona says, “Ding, dong, the witch is dead.” This is from a song in The Wizard of Oz.
The title of the Angel episode Over the Rainbow is another reference to The Wizard of Oz, in which the land of Oz is said to be ‘over the rainbow’. In that episode, Cordelia clicks her heels three times (as Dorothy does in the film) and says, “Worth a shot.”