Board Thread:General Discussion/@comment-27894627-20160511021754/@comment-29633527-20160814171835

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". As for this, you're wrong, Toby himself refers to Mettaton as a HE in several Twitter posts.