Board Thread:General Discussion/@comment-27894627-20160511021754/@comment-27330113-20160805195415

Shadrixian wrote: It's a robot. Robots don't have a gender. Toby never specifies what gender Mettaton is. It is referred to as he, it, but never "she". Robots do not have biological gender, but they can have it mentally

(Also, Mettaton is a magical robot with soul, he can be a "he")