How to set back button text in Swift

Question

The back button belongs to the previous view controller, not the one currently presented on screen.
To modify the back button you should update it before pushing, on the view controller that initiated the segue:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    let backItem = UIBarButtonItem()
    backItem.title = "Something Else"
    navigationItem.backBarButtonItem = backItem // This will show in the next view controller being pushed
}

Swift 3, 4 & 5:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let backItem = UIBarButtonItem()
    backItem.title = "Something Else"
    navigationItem.backBarButtonItem = backItem // This will show in the next view controller being pushed
}

OR

// in your viewDidLoad or viewWillAppear
navigationItem.backBarButtonItem = UIBarButtonItem(
    title: "Something Else", style: .plain, target: nil, action: nil)

You can do it from interface builder as follows:

click on the navigation item of previous view controller

from the attributes inspector set the back button text to whatever you want. Thats it!!

You can put this 3 line of code in the ViewController you want to change the back button title.

In your override func viewDidLoad() {}.

let backButton = UIBarButtonItem()
backButton.title = "My Back Button Title"
self.navigationController?.navigationBar.topItem?.backBarButtonItem = backButton

Back-button text is taken from parent view-controller's navigation item title. So whatever you set on previous view-controller's navigation item title, will be shown on current view controller's back button text. You can just put "" as navigation item title in parent view-controller's viewWillAppear method.

self.navigationItem.title = ""

Another way is to put

self.navigationController?.navigationBar.topItem?.title = ""

in current view controller's viewWillAppear method. This one will cause some other problem if navigation stack is too nested.

If you are using xib file for view controller then do this in your view controller class.

class AboutUsViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    edgesForExtendedLayout = []
    setUpNavBar()
}

func setUpNavBar(){
    //For title in navigation bar
    self.navigationController?.view.backgroundColor = UIColor.white
    self.navigationController?.view.tintColor = UIColor.orange
    self.navigationItem.title = "About Us"

    //For back button in navigation bar
    let backButton = UIBarButtonItem()
    backButton.title = "Back"
    self.navigationController?.navigationBar.topItem?.backBarButtonItem = backButton
}

}

The result will be: