The first and second series of the television show Round the Twist were written by Paul Jennings and based on his published short stories; episodes after this point were original stories written by other people. The lesser-known series Driven Crazy was likewise based on his previously unadapted stories.
Co-authored two series with Morris Gleitzman: Wicked! and Deadly!.
His work is often quirky in style, often drawing upon weird, spooky and fantastical occurrences, including liberal amounts of gross-out humour and Nightmare Fuel. For these last reasons especially, Moral Guardians have frequently questioned the appropriateness of his work for younger readers. For much the same reasons, these younger readers have often loved it.
Jennings' work provides examples of:
- Accidental Misnaming: Absent-Minded Professor Dr Woolley in The Copy can't remember Tim's name and calls him things like Peter or Rodney.
- All of the Other Reindeer: Peter's classmates bully him in Pubic Hare because he's the only kid in Year Seven with pubic hair.
- Ambiguous Clone Ending: Played With - The Copy has the same memories as Tim, and becomes convinced that he is the original, and that "The Copy" is trying to live his life. It soon turns out the story from after Tim uses the copy machine and passes out is told using the clone's memories instead of the original's, and Tim is dead.
- Ambiguous Ending: Many examples, one being One-Shot Toothpaste. While Antonio is having treatment, Mr Bin the dentist tells him a story about a horrible old man with one fusty green tooth. The old man was trying to develop One-Shot Toothpaste by testing it on animals until the young Mr Bin broke in and discovered his plan. Mr Bin used the toothpaste on him, causing his tooth to grow until his body vanished. As Antonio leaves, he notices the paint is peeling off the dentist's big tooth-shaped sign, revealing its fusty green colour... but then the dentist starts to tell a contradictory story to his next patient. So...was the dentist's story true or just made up to take his young patients' mind off the pain?
- Ambiguous Gender: Beethoven, the budgie in Only Gilt, and Ohda, the dog in Smelly Feat, are only referred to as "it" instead of "he" or "she".
- And I Must Scream: Cantankerous old Aunt Scrotch accidentally swaps bodies with a dung beetle at the end of Mousechap.
- Animal Lover: They often pop up in his work, such as the dad in The Hat and Uncle Sam in Picked Bones.
- Anyone Can Die: Don't ever presume an individual is safe from death just because of traits like their age or species; he'll happily kill off kids and pets.
- Artistic License – Animal Care: Philip, the kid in Too Many Rabbits, feeds his rabbit nothing but carrots at first - it's not good for rabbits to eat carrots except as a treat since they are too high in sugar and low in fibre.
- Artistic License – Biology: The main character of Smart Ice Cream claims he's so smart, he could talk in full sentences the day he was born. This isn't possible no matter how smart you are, as babies' muscles and vocal cords need time to develop before they can say actual words.
- Baffled by Own Biology: In the story Nails, the protagonist Lehman has what appears to be nails growing all over his body, and his father tries to find a cure. As it turns out, Lehman's biological mother was actually a mermaid, making him a human-mermaid hybrid, and the "nails" were actually scales. He was slowly transforming into a merman all along.
- Bait-and-Switch: What Weesle is training for in Little Squirt.
- Barred from the Afterlife: When his stories feature ghosts, they usually need the protagonist's help to move on due to Unfinished Business, such as in Cracking Up and Trashed.
- Be Careful What You Wish For: His favourite Aesop is you should always consider if you really, really want what you think you want.
- Big Brother Bully: Gordon from Inside Out; Gobble/Arnold from The Velvet Throne and Simon from Ringing Wet.
- Body Horror: The main characters of Burp and Nails, amongst others; the former bloats up until he becomes so morbidly obese that his heart can't take the strain and he dies, his final words being a loud belch, whilst the latter has finger and toenails sprout all over his hands, feet, arms and legs until it turns out they're actually scales and he's turning into a merman. Clear As Mud uses it twice.
- Body to Jewel: The main character of Tonsil Eye 'Tis grows a third eye on his finger that cries tears that grow into garden gnomes. In the end, he starts a business selling them.
- Can't Get Away with Nuthin': Byron in Shake refuses to shake hands and make up with his twin brother Gavin after an argument. Gavin then runs out of the house into the road and is killed by a car.
- Cassandra Truth: Played with in Ringing Wet. Misty is convinced her neighbour has murdered his wife due to his shifty behaviour, but naturally, her parents don't believe her. Later, it turns out she was right to suspect him - he and his wife have been burgling houses for years and have stolen thousands of dollars' worth of jewellery. However, she was wrong about him killing his wife.
- Clothes Make the Maniac: The acrobat's outfit in Know All, where the scarecrow becomes evil when it wears the acrobat's outfit, because it belonged to an evil person. The other circus clothes do similar things, with Matthew fooling when he dresses in the clown's costume then throwing knives perfectly when he wears the knife thrower's costume. Kate uses this at the end by wearing the fortune teller's costume.
- Demorphing Denouement: Played with in Burp! Here, the overweight protagonist discovers a spell that can transfer his weight to other people, and quickly begins abusing the power for the sake of revenge and sadism. However, he learns too late that when the spell finally expires after four years, everything he transferred will be returned. Worse still, the protagonist did a lot of binge-eating to build up the necessary weight before using the spell on his victims of choice - so what he gets back isn't just his original weight, but his original weight 'with interest'. As a result, he grows so fat that he bursts out of his clothes, fills up the entire room, and dies of a heart attack.
- Downer Ending: Many stories end in depressing or morbid fates for the narrator.
- The End... Or Is It?: A bushfire burns down the magical gum tree in The Gum Leaf Wars, so the protagonist's grandpa and his neighbour can no longer use its leaves to pass illnesses to each other. They make friends and the protagonist leaves to go back to his parents' house. Then, while he's on the train home, a park ranger tells him that gum trees usually spring back to life after bushfires...
- Failed Attempt at Scaring: In Inside Out, Gordon, a horror film buff, goes to the local Haunted House and finds himself incredibly bored by all the horrifying phenomena he witnesses. Unfortunately, the ghost haunting the place is trying to pass an exam, and if he can't scare Gordon in the allotted time, the ghost will have to retake the exam - leaving Gordon trapped until he can be used as a victim all over again next semester. So, Gordon does his best to look scared at the ensuing display of fearsome gimmicks, even though he's Seen It All. What actually works is the ghost demonstrating a talent for magically turning objects inside-out, and then gearing up to use it on the protagonist. The examiner gives the ghost an excellent grade and Gordon is allowed to go free... but is left scared of everything as a result of his experiences.
- Faking the Weather: In "For Ever" in Uncovered, Tim is slowly dying of an unspecified terminal disease, and he has a Tragic Dream to see it snow. His brother Richard collects toilet paper and his family members think it's just a weird hobby of his, but at the very end, we learn the true reason. When Tim is near death, Richard tears up the toilet paper and throws it out the window so that Tim will think that it's snowing, so he dies happy.
- Feghoot: Many of his stories end with a pun. For example, the whole of On The Bottom leads up to a pun on the words "bear" and "bare".
- Fish out of Temporal Water: One story concerns a boy who gets trapped in a room at the bottom of a well for fifty years and becomes a ghost. He's able to escape by forcing another boy to take his place, and notes how much the world has changed.
- Great Accomplishment, Weak Credibility: The narrator of Smart Ice Cream is a Child Prodigy and an Insufferable Genius who is usually the only one in his class to get full marks in math. So when his classmate Dadien also gets full marks, the protagonist, who believes all his classmates are dumb, thinks Dadien must have cheated. He thinks it was because he'd eaten Smart Ice-Cream, but after the protagonist eats it too, he guesses just before the effects take hold that he made a mistake.
- Hoist by His Own Petard:
- In Smart Ice Cream, the Jerkass narrator is a know-it-all bully who regularly taunts and teases people while scoring high on tests. Over the course of the story, the people who he taunts and teases receive free ice cream from a mysterious ice cream man, and subsequently lose the trait he was teasing them about (e.g. a pimply-faced character's acne disappears overnight). Infuriated that he doesn't get any ice cream, he breaks into the man's truck at night and puts sand in every tub but the one labeled "Smart Ice Cream - for smart alecks" which he helps himself to. The final part of the story is riddled with spelling and grammatical errors, as the narrator wonders what happened...and can't work out whether one plus one is "free or for?"
- Also, the Gizmos in the Gizmo series wouldn't have caused so much trouble if the characters had just left them alone in the first place.
- Giffen from The Strap-Box Flyer sells a miracle glue that holds anything together...for four hours, at which point it falls apart. He never tells anyone of this limitation, leading to a trail of sorrows from the destruction of prized belongings to a child drowning. He runs into a man who invented the strap-box flyer, which lets you fly. As they fly towards the clouds, all sense of time lost, the inventor casually reveals the conman's flyer is held together with his glue, and just then it falls apart.
"He screamed all the way down."- In No Is Yes, Dr Scrape has isolated his daughter, Linda, and spoken in a way that has taught her all the wrong words to everything. When their house catches fire and he is trapped inside, a fireman asks her if anyone is in there. She replies "No", because she thinks that no means yes. Her father has literally killed himself because his daughter lacks the means to properly communicate with others. It is suggested that she began to understand that she had been taught the wrong words and may have left her father to die on purpose, but from Linda's earlier behaviour, it is more likely she still thought "no" meant "yes".
- Hurricane of Puns: His joint books with Ted Greenwood and Terry Denton, Spooner Or Later and Freeze A Crowd.
- Jerkass: One will always show up in his stories, usually as an antagonist, rarely as a protagonist. In the Gizmo books, the protagonist typically does something wrong for the approval of this kind of character.
- Karmic Death: The abovementioned Villain Protagonist of The Strap-Box Flyer, whose lies lead to a death during the course of the story — a boy he sells his glue to drowns after his broken canoe falls apart again when the glue wears off while he's sailing it — and are implied to have caused similar deaths in the past.
- Karmic Transformation:
- The seemingly fearless Big Brother Bully narrator, Gordon, of "Inside Out" is scornful toward and inconsiderate of his easily-scared sister. Wandering into an abandoned house at night, he is compelled to be the subject of a ghost's spooking exam, which the ghost passes by magically turning various objects inside out and then almost doing the same to Gordon, causing him to faint. He escapes physically unharmed but has lost his fearlessness and become even more timid than his sister; he now jumps at every sound and describes the Muppet movie she is watching as "really creepy".
- The narrator of "Smart Ice Cream" is a very smart but horrible boy who bullies his classmates for their appearance, has contempt for those who are less smart, and can't abide anyone else getting marks as good as his on school tests. When those on the receiving end of his bullying are helped by a kind ice-cream seller who gives them magical transformative ice-cream which makes their problems fade away, the narrator ransacks and vandalizes the ice-cream van, discovers the titular "smart ice-cream for smart alecs", and greedily eats it. It causes him to lose all of his intelligence, putting him far behind the classmates he previously looked down on.
- Laser-Guided Karma: Bullies and other nasty people almost always get their comeuppance in his short stories.
- Lethally Stupid: If Jason in The Hat had just left his late mum's hat indoors or even worn a different one, it wouldn't have blown away and caused him to leave his post, resulting in a rat killing the endangered bilby he was meant to be guarding.
- "Magic A" Is "Magic A": His Twist Endings frequently follow logically from a previously established trait or truth of the work.
- Malaproper: Philip in Too Many Rabbits gets all his sayings wrong and says things like "too big for your brutes" and "making lends meet".
- Men Are Better Than Women: Played with in What A Woman. Sally is the only girl in her whole school and all the boys make fun of her because she comes last in all the Mini-Olympics events. Sally eventually proves them wrong when her athletic aunt's paperweight/trick box brings her good luck in both sports and other unrelated things. Eventually, the box is opened and all the boys faint to find her aunt's toe inside, while Sally doesn't. This is especially important since Sally's main tormentor has mentioned twice that only girls faint, so he proves that men are actually more faint-hearted than women.
- Mooning: The story Moonies revolves around the protagonist, Adam, being forced by a bully to flash his naked butt at people driving along a road. He manages to get even by getting the bully to do the same... after Adam drew a very recognizable caricature of the bully's face on his arse, so the teacher he's mooning instantly realizes who it is.
- Mythology Gag: In Listen Ear, Brad says his favourite TV show is Round the Twist. Most of the episodes were based on Jennings' stories and he wrote the scripts for the first two series.
- Naked People Are Funny: A lot of stories involve the characters being caught naked in public e.g. The Gizmo, Wunderpants and Pubic Hare.
- Never the Selves Shall Meet: One story is about a little boy called John who jumps nine years into the future. When he's older, he realises that the big boy he saw on the day he time-travelled was actually an older version of himself, trying to change the past so his mother doesn't die in a road accident. It's left unclear whether the plan worked or caused him to disappear from the timeline entirely.
- Oblivious to Love: The narrator of "Ex Poser", David, has a bad case of this. Using a lie detector to try to embarrass the two quiet, good-looking rich kids in the class whom he dismissed as snobs and mistakenly thought were together, he does not realise that he is the rich girl's crush.
- Our Mermaids Are Different: In Nails, mermen and mermaids can crossbreed with humans, with said offspring looking human until puberty, when they will start to grow what look like extra fingernails (really fish scales) up their fingers and eventually over various parts of their body, shortly before their legs fuse together to become the iconic tails.
- Outgrowing the Building: In Burp!, the Big Eater protagonist discovers a spell that can transfer his weight to anyone he chooses. He quickly abuses its power to get revenge on anyone who he dislikes, gorging himself in advance for maximum humiliation of his victims... only to learn too late that the spell will only last four years before all the weight will be transferred back to him. In a matter of minutes, he gets so obese that he bursts out of his clothes and fills up the whole room, ending up trapped inside with one leg sticking out the window; for good measure, his ballooning weight is too much for his heart and he dies soon after.
- Parting-Words Regret: The core conflict in Shake is that Byron refused to make up with Gavin after their only fight, and Gavin died just after trying to make up. Byron swears that he'll never be happy until he can shake hands with Gavin and make up. They end up being able to see each other one more time, using supernatural glasses that allow them to communicate with each other, and they finally shake hands.
- Picky People Eater: The Slobberers from the series Wicked! only eat flesh, bones and organs, not skin or hair. So their victims are left as hollowed out, dessicated skins when the Slobberers are done with them.
- Potty Failure: Ringing Wet revolves around a girl called Misty who has a bedwetting problem. She also has an accident at Luna Park when her brother, Simon, tricks her into going on a scary ride.
- Pun-Based Title: His short stories almost all have punny titles. The reader can sometimes use them to guess what will happen at the end.
- Punny Name: M.T. Binnote empty bin, the dentist in One-Shot Toothpaste.
- Ripped from the Headlines: Greensleeves was inspired by a real incident that occurred in Florence, Oregon in 1970 when the town tried to dispose of a beached whale with explosives.
- Scary Scarecrows: Know All features a scarecrow coming to life when it wears an acrobat costume due to a circus curse. Kate recognizes that the costume belonged to someone bad, and the costume passes on the person's evil.
- Shout-Out: Misty in Ringing Wet makes one to The Famous Five, which also foreshadows the Cassandra Truth in her own story."I am reading a book where five kids go on holiday. They discover smugglers in some underground caves but the adults won't believe them."
- Teasing Parent: In the short story "A Mouthful", the protagonist's father loves to play pranks on his daughter and her friends. He's put too much pepper on their dinner, short-sheeted the beds, etc, but his favourite prank was to put fake cat poop on the table and pretend to eat it. The girl then tricks him into eating real cat food.
- Toilet Humour: Pretty much a given in his short stories, seeing as they're aimed at kids aged 8-12. Also, if a large animal such as a cow or horse appears, there's probably about an 80% chance it's going to unload a massive poo at some point.
- Tomato Surprise and Tomato in the Mirror: A number of his stories, but notably The Copy.
- Tongue on the Flagpole: The story Ice Maiden features a boy kissing an ice sculpture and getting stuck.
- Toothy Bird: Picked Bones has two birds with teeth given to a boy called Terry, with a warning to keep them away from his cat. He assumes it's because the cat will harm the birds. It turns out that this is not the case.
- Universal Remote Control: In the story "Spaghetti Pig-Out", a boy called Matthew gets a remote that looks like a green chocolate bar that can control not only the VCR but people, flies, and cats.
- Verbal Tic:
- Without a Shirt is about a boy called Brian who can't help adding the titular phrase to everything he says without a shirt.
- Misty in Ringing Wet has a habit of repeating a phrase she's just said in capitals preceded by "Yes"."I do it on purpose. Yes, ON PURPOSE."
- Weaponized Stench: In Smelly Feat, a boy called Berin saves a sea turtle from being slaughtered by using his feet that he didn't wash for months to stop the bully that was going to kill her as she laid her eggs.
- Wild Child: Philip in Batty has lived in the forest since he was five and has all but forgotten how to speak.
- Wipe That Smile Off Your Face: The last line of Santa Claws is, "I wish you didn't have such a big mouth."
- You Can't Fight Fate: Looking into the eye of a Seeshell lets you see the future, and everything you see will happen — attempting to avert what you see will just create a Self-Fulfilling Prophecy — however, you can also manipulate fate to change the circumstances of what you saw.