Set the NSFetchRequest property sortDescriptors to determine how data is returned.

let fetchRequest = NSFetchRequest(entityName: "NAME_OF_ENTITY")
let sortDescriptor = NSSortDescriptor(key: "NAME_OF_ATTRIBUTE", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]

You can also set multiple sort descriptors, to sort by one attribute within another. For example, return all entries ordered by date, and by name within each date:

let fetchRequest = NSFetchRequest(entityName: "NAME_OF_ENTITY")
let sortDescriptor1 = NSSortDescriptor(key: "name", ascending: true)
let sortDescriptor2 = NSSortDescriptor(key: "date", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor1, sortDescriptor2]