Orange Monster Kid's Name?

[Flexico]

Does (s)he even have a name, mentioned in the game? I never caught it.

[Papa Crust]

Nah. His name is Monster kid.

[Kptn Howdy]

Monster Kid

[Flexico]

Haha ok cool

[TheAudacity]

I believe Toby said it was just "Kid"
I could be wrong though.

[Blessed Evelyn]

Koby Brant

[Zeox]

Monster Kid
MK for friends
Kiddo
"Yo" monster
Yellow lizard with no arms

[A Fat, Angry Serval]

Most people just call him Monster Kid, though I have another name for him...

...Undyne's #1 Fan.

[Blessed Evelyn]

Richard Shelby

Originally posted by Self-diagnosed meme addict:

Ted Cruz

[Jamchow]

Tai Lopez.

[Kptn Howdy]

Originally posted by ☼ Jamchow ☼:

Tai Lopez.

Lai Topez

[CTA]

John Cena?

[Kptn Howdy]

Originally posted by VeggieTables | I am bad at CS:GO:

John Cena?

Nope, Chuck Testa

[Blessed Evelyn]

Originally posted by Mora Linda~:

plz stop with the john cena meme it was never funny to begin with

And his name is Johnathan Cerosa

[ditt_25]

Credits list the character as Monster Kid.
Out-of-Game materials (i.e. Toby posting on Twitter, etc) sometimes calls the character Kid.
Gender is not specified, neither ingame nor officially out-of-game, as far as I can tell.

Forgot if MK is referred to as "they," "them," etc. at any point or not. But there are three notable characters referred only to as "they" or "them" instead of "him" or "her."

The other three being

Napstablook and two humans

[CrazieDazie]

smol alphys child