Swift

textField.autocapitalizationType = .None

Objective-C

textField.autocapitalizationType = UITextAutocapitalizationTypeNone;

All options:

• .None \ UITextAutocapitalizationTypeNone : Don’t autocapitalize anything
• .Words \ UITextAutocapitalizationTypeWords : Autocapitalize every word
• .Sentences \ UITextAutocapitalizationTypeSentences : Autocapitalize the first word in a sentence
• .AllCharacters \ UITextAutocapitalizationTypeAllCharacters : Autocapitalize every letter (i.e. caps lock)