There was even a film made about the competition called Spellbound that has won lots of awards.
TV cameras will be at heats and will follow the lives of some of the children all the way to the final.
Some teachers aren't sure the contest will be a good thing for the children, but Schools Minister Steven Twigg reckons it's a good idea.
He said: "Anything which helps raise the awareness of the hard work our pupils put into spelling is a good thing."