Timmy Turner is the main character of the show. He is a miserable ten year old who one day was granted magical Fairy Godparents because he was being tormented by his mean babysitter, Vicky. His godparents, Cosmo and Wanda, aren't the brightest or the best at their job, but they can still grant pretty much any wish, even if the consequences aren't as intended. Timmy has been both progressed and regressed several times throughout the show, from becoming a balding middle aged man, a muscular man in the prime of his life, a teenager, and several other times he became a baby.

Cosmo and Wanda are magical fairy godparents that have been around for thousands of years. They are just two of many fairies from Fairy World, a race of mythical creatures that can grant wishes to children who are miserable and unhappy. Sometimes, however, the wishes they grant don't always turn out as expected. Sometimes in the show Cosmo likes to wear diapers.

Vicky is a sixteen year old girl who babysits children around Dimmsdale for money. In front of parents, she acts sweet and nice, but when she is left alone with their kids, she becomes extremely evil and tortures children. Her most frequent victims are Timmy, who she calls "the twerp", and her Timmy-loving little sister, Tootie. At one point in the show, Timmy wished Vicky into a five year old girl so he could get revenge on her.

Poof is the newborn son of Cosmo and Wanda, the first baby fairy born in thousands of years. When he cries it causes worldwide magical destruction.

She is the prettiest and most popular girl in Dimmsdale Elementary School. She is the same age and in the same class as Timmy but is far taller and more mature than him, and regards Timmy and his friends to be geeks. Despite this, Timmy will stop at no length to woo her.

Unlike her older sister Vicky, Tootie loves Timmy to the point where her room is a shrine of pictures and other Timmy merchandise. She is a geeky looking girl who gets very excited or upset easily, and often cries because of Timmy ignoring her. At one point in the show, she had a bathroom accident off screen and did not seem bothered by it.

Veronica is also another girl that is said to like Timmy, although unlike Tootie her crush is kept a secret. This is because she is also a popular kid like Trixie and fears that by not looking down on Timmy and his friends, she could lose her status as "second most popular girl in Dimmsdale Elementary". Bad luck always seems to follow her around, at one point she lost all her clothes except her undies in the middle of the mall.

An extremely rich boy who also has godparents, because even though he is rich and has everything he wants, his parents still ignore him just as bad as Timmy's parents ignore Timmy. He has many times tried to hurt Timmy or cause Timmy to lose his fairies.