Oz is a realm featured on ABC's Once Upon a Time.
- Zelena Mills - (formerly) Witch of the West, later known as the Wicked Witch of the West
- Witch of the East
- Witch of the North
- Glinda - (formerly) Witch of the South, later banished to the Enchanted Forest by Zelena
- Walsh - (formerly) arrived from Kansas and became the Wizard of Oz
- Dorothy Gale - visited from Kansas, before returning to Oz to defeat Zelena
- Flying Monkeys - Zelena's winged simian servants during her reign
- Ruby Lucas
- Woodsman's wife
- Will Scarlet (formerly)
- Robin Hood (formerly)
- Snow White (formerly)
- Based on the Land of Oz that appears in The Wonderful Wizard of Oz.
- S1, E17: "Hat Trick" (portal)
- S3, E16: "It's Not Easy Being Green" (flashback)
- S3, E20: "Kansas" (flashback)
- S4, E17: "Heart Of Gold" (flashback)
- S5, E16: "Our Decay" (flashback)
- S5. E18: "Ruby Slippers"
- S5, E19: "Sisters" (flashback)
- S6, E18: "Where Bluebirds Fly" (flashback)