Are there any books or otherwise fictional literary works about what would happen if all adults 13 and over disappeared, leaving kids 12 and under to run the world themselves?

http://www.gerenser.com/lotf/
Lord of the Flies by William Golding

The book doesn't fit the exact scenario described but would still be highly useful to someone who is curious about this theme. The book is a very good read.

It was made into two movies, one good (the original) and one not-so-good.

Awhile ago I read a book titled "The Girl Who Owned A City" by O.T. Nelson.
This is an excerpt from the back cover

"A killing virus has swept the earth, sparing only children through the age of twelve. There is chaos everywhere, even in formely prosperous mid-America. Gangs and fierce armies of children begin to form almost immediately. It would be the same for the children on Grand Avenue but for Lisa, a yen-year-old girl who becomes their leader. Because of Lisa, they have food, even toys, in abundance. And now they can protect themselves from the fierce gangs that roam the neighborhoods. But for how long? Then Lisa conceives the idea of a fortress, a city in which the children could live safely and happily always, and she intends to lead them there."

I thought this was a good read and I hope you enjoy it.

There was an episode of the original Star Trek that had a premise similar to this. They found a planet where some sort of disease caused children to to age much more slowly than normal, and was otherwise harmless to children. The disease was fatal to adults, however, and as the children eventually reached puberty, they died of the disease.

The series "Left Behind >The Kids<" does this. The author is the well-known Tim LaHaye and Jerry B. Jenkins. They've been writing the Left Behind series for ten years, and it's an amazing set of novels!

A great book with this basic plot would be " The Girl Who Owned A City" by O.T. Nelson. Basically, everyone in the world over the age of 12 has died from a great plague and how the children left behind survive in this new and hostile world. It's a great book that really begs the question 'what if this did happen..'

This is also the premise of the graphic novel and television series Jeremiah. Everyone above the age of innocence (puberty) was wiped out by a plague, leaving just children behind. The story takes place ten years later and follows a young man named Jermiah and his friend Kurdy as they travel and meet different groups of young people, all of whom are warring since they've been left without the guidance and social framework of their elders. (The TV show aired in the US on Showtime, but has since been cancelled.)

I know, this isn't a book, but I think the graphic novel *might* qualify as a "fictional literary work" and it did seem to fit the concept very well.