这适用于Swift <3.0:

myTextField.attributedPlaceholder = 
NSAttributedString(string: "placeholder text", attributes: [NSForegroundColorAttributeName : UIColor.redColor()])

在iOS 8.2和iOS 8.3 beta 4中测试。

斯威夫特3:

myTextfield.attributedPlaceholder =
NSAttributedString(string: "placeholder text", attributes: [NSForegroundColorAttributeName : UIColor.red])

斯威夫特4:

myTextfield.attributedPlaceholder =
NSAttributedString(string: "placeholder text", attributes: [NSAttributedStringKey.foregroundColor: UIColor.red])

斯威夫特4.2:

myTextfield.attributedPlaceholder =
NSAttributedString(string: "placeholder text", attributes: [NSAttributedString.Key.foregroundColor: UIColor.red])

此解决方案适用于Swift 4.1

    textName.attributedPlaceholder = NSAttributedString(string: textName.placeholder!, attributes: [NSAttributedStringKey.foregroundColor : UIColor.red])

我能做的最好的iOS7和更少的是:

- (CGRect)placeholderRectForBounds:(CGRect)bounds {
  return [self textRectForBounds:bounds];
}

- (CGRect)editingRectForBounds:(CGRect)bounds {
  return [self textRectForBounds:bounds];
}

- (CGRect)textRectForBounds:(CGRect)bounds {
  CGRect rect = CGRectInset(bounds, 0, 6); //TODO: can be improved by comparing font size versus bounds.size.height
  return rect;
}

- (void)drawPlaceholderInRect:(CGRect)rect {
  UIColor *color =RGBColor(65, 65, 65);
  if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
    [self.placeholder drawInRect:rect withAttributes:@{NSFontAttributeName:self.font, UITextAttributeTextColor:color}];
  } else {
    [color setFill];
    [self.placeholder drawInRect:rect withFont:self.font];
  }
}

也许你想尝试这种方式，但苹果可能会警告你访问私有ivar:

[self.myTextField setValue:[UIColor darkGrayColor] 
                forKeyPath:@"_placeholderLabel.textColor"];

请注意 根据Martin Alléus的说法，iOS 7不再适用了。

在Swift 3中

import UIKit

let TEXTFIELD_BLUE  = UIColor.blue
let TEXTFIELD_GRAY  = UIColor.gray

class DBTextField: UITextField {
    /// Tetxfield Placeholder Color
    @IBInspectable var palceHolderColor: UIColor = TEXTFIELD_GRAY
    func setupTextField () {
        self.attributedPlaceholder = NSAttributedString(string:self.placeholder != nil ? self.placeholder! : "",
                                                            attributes:[NSForegroundColorAttributeName: palceHolderColor])
    }
}

class DBLocalizedTextField : UITextField {
    override func awakeFromNib() {
        super.awakeFromNib()
        self.placeholder = self.placeholder
    }
}

有了这个，我们可以在iOS中改变文本字段占位符文本的颜色

[self.userNameTxt setValue:[UIColor colorWithRed:41.0/255.0 green:91.0/255.0 blue:106.0/255.0 alpha:1.0] forKeyPath:@"_placeholderLabel.textColor"];