Gather all your ingredients and equipment.
Juice the fresh oranges to get 1 cup of juice.
In a blender, combine the orange juice, milk, sugar, and vanilla extract.
Add the ice to the blender.
If using, slice the banana and add it to the blender.
Blend on high until smooth and creamy.
Taste the mixture and adjust sweetness, if desired.
Pour the Orange Julius into glasses.
Garnish with a slice of orange on the rim.
Serve immediately and enjoy your refreshing drink!