How to disable default Widget splash effect in Flutter?

Per @hunter’s suggestion above, I found that by setting both highlightColor and splashColor in my theme to Colors.transparent removed the ripple.

I do hold some concerns that setting highlightColor might have some knock-on effects, but I haven’t noticed any yet.

Edit: While my original answer has loads of up-votes, the more I learn, the more I’ve realised that it really isn’t the right way to do it. As several people have pointed out below, a better solution is to use the splashFactory. For example, the code below shows it being set directly via the style, or you can set it in your theme too:

ElevatedButton(
  onPressed: onPressed,
  style: ElevatedButton.styleFrom(
    splashFactory: NoSplash.splashFactory,
  ),
  child: child,
);