The sketch show features a number of young cast members such as Son of Rambow star Will Poulter.
Returning characters include a cockney taxi driver, the White Van Men, movie executives Karl and Marv and the Museum Perv.
Meanwhile, E4 announced that new sketches will focus on a pair of 1970s policemen, the mother of a mafia family, a businessman from the 1980s and Hector The Lookalike, who puts on a number of guises from Idi Amin to Gary Glitter.
The show's producer Jenna Jones said: "These kids have an energy and enthusiasm for comedy that is infectious. They are an exciting, inventive bunch of kids that just have a very natural feel for comedy - they've been performing sketches since they were 11 years old."
Meanwhile, executive producer Andy Harries added: "It's rather blissful working with a bunch of actors without any egos. Really, the biggest problem we had on set was too much laughter."
School Of Comedy returns on September 13 on E4.