How can I set the title of a UIButton as left-aligned?

Question

Set the contentHorizontalAlignment:

emailBtn.contentHorizontalAlignment = .left;

You might also want to adjust the content left inset otherwise the text will touch the left border:

emailBtn.contentEdgeInsets = UIEdgeInsetsMake(0, 10, 0, 0);

// Swift 3 and up:
emailBtn.contentEdgeInsets = UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 0);

You can also use interface builder if you don't want to make the adjustments in code. Here I left align the text and also indent it some:

Don't forget you can also align an image in the button too.:

In Swift 3+:

button.contentHorizontalAlignment = .left

Swift 4+

button.contentHorizontalAlignment = .left
button.contentVerticalAlignment = .top
button.contentEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)

UIButton *btn;
btn.contentVerticalAlignment = UIControlContentVerticalAlignmentTop;
btn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;

Using emailBtn.titleEdgeInsets is better than contentEdgeInsets, in case you don't want to change the whole content position inside the button.

Here is explained how to do it and why it works so: http://cocoathings.blogspot.com/2013/03/how-to-make-uibutton-text-left-or-right.html