He has also written and starred in the television series Big School and his series of children's books; The World Of Walliams:
- The Boy in the Dress
- Mr Stink
- Billionare Boy
- Gangsta Granny
- Ratburger
- Demon Dentist
- Awful Auntie
- Grandpas Great Escape
- The Midnight Gang
- Bad Dad
- The Ice Monster
- The Worlds Worst Children (with three volumes and counting)
Tropes associated with his work include:
- Annoying Younger Sibling:
- Annabelle in Mr Stink to Chloe.
- Averted in The World's Worst Children series, where it's usually in fact the older siblings - Bonnie Bossypants, Honey the Hogger, Bertha the Blubberer - who make their younger siblings lives miserable.
- Camp Straight: When paired with Matt Lucas, he's certainly this to Lucas' Straight Gay.
- Card-Carrying Villain: A lot of his villains tend to take pleasure in being called out on how sick they are.
- Creator Cameo: He appears in every book-to-TV-film adaptation of his works.
- Crying Wolf: After Bertha the Blubberer gets caught in the act trying to frame her brother for pulling out her hair, no one believes her when William gets some revenge by pinching her under the table because she's claimed the same thing so many times before.
- Determinator: In The World's Worst Children, vol. 1, Brian Wong is determined to count to infinity. He's interrupted on his death bed for the last time.
- Enfant Terrible: The premise of his World's Worst Children series.
- Family-Unfriendly Death: Several villains meet surprisingly gruesome ends in his books. A few non-villains too.
- Sheila and Burt in Ratburger are ground into mincemeat and made into burgers after they fall into the latter's pulverisation machine. A bunch of rats earlier in the book meet the same fate.
- The tooth witch and her cat from Demon Dentist a first knocked into a cauldron of their extremely corrosive toothpaste by a locomotive, then their still-sentient skeletons are crushed by a falling elevator.
- Aunt Alberta is carried into the sky by an army of birds, then dropped to her death, which shakes the entire ground.
- The Beast of Buckingham Palace has the highest amount of death scenes of all his booksnote . Two beggars are shot to death and fall into the Thames, the leader of an elderly group resisting the dystopian present is shot In the Back and drifts down the Thames, the protagonist's traitorous Nanny is stabbed in the back by the Queen with a machete, the Lord Protector is graphically fused with the titular beast and the King is burned to a pile of ashes by this fusion.
- Gasshole: Windy Mindy of The World's Worst Children.
- Good Is Dumb: Barry Bovver of The World's Worst Parents. He's by no means a bad father to his daughter but his limited intelligence ends up causing a lot of trouble.
- The Pig-Pen: Grubby Gertrude and Gruesome Griselda, two of The World's Worst Children who delight in being disgusting.
- Precision F-Strike:
- His earlier books contained minor cursing. For example, Mr Hawtrey says "Where the hell are they?" in The Boy in the Dress.
- Even some books after his earlier ones have some questionable language, like Soot the ghost from Awful Auntie using the term "short-arse".
- Sadist Teacher: Many of the teachers in The World's Worst Teachers. Some, however, are just incompetent.
- Sickening Sweethearts: Mr and Mrs Lovey-Dovey. For this reason they make the list of the World's Worst Teachers.
- Stage Name: His real surname is Williams.
