Triple boot is possible?

Win + Linux + macOS?
On the right hardware, sure

Of course, technically you can have as many boot entries as you want

Grub can even boot from local iso. It has a lot of possibilities...

Just remember that hdd partitioned with mbr table has a limit of 4 physical partitions, but you can have more logical. Do some research and you can set it right.

@juzles is absolutely right. When I first installed Ubuntu on a Windows machine (dual boot), I just tried if I could install another OS. But do a solid research first.

Why would anyone use MBR?

You could also run a bunch of other OSes, like BSD, ReactOS and Haiku.

@osmarks I do believe you need mbr to boot windows 10

@liammartens
Really? I'm pretty sure it can use GPT.

Edit: checked, booting from it is supported if UEFI is used and on 64-bit systems.

Win10 can boot with gpt but if you already installed it as mbr it's not that easy to convert

I even think most of the preinstalled win10 from laptop oem are using gpt now

@juzles I havent bought a new laptop in a while so I may be out of date

I do triple boot with three Linux distro's...