It does, but the ability to press F8 at bootup to invoke it has been removed. To get to safe mode in Windows 8/8.1, you need to set Windows to reboot into safe mode on the next startup before you log out of a session. There are some features which are supposed to automatically repair Windows if it doesn't boot (though we know they don't always work).
Well,technically there is a shift-F8 key combination to achieve safe mode on a reboot, but it's hard to hit in practice. It seems Windows times out that pretty quickly. I've tried it a few times on my desktop and couldn't hit it.