The Moomin family
- Moomintroll (Mumintrollet) (Also simply Moomin) - the main character of most of the books, a spirited troll with a keen sense of adventure and fun. Moomin lives life fully, and views the world with a feeling of wonderment for such simple pleasures as collecting stones and shells. As gullible as he is enthusiastic, he is also naive and extremely good-natured. He has a secret love affair with The Snork Maiden.
- Moominmamma (Muminmamman) - the mother of Moomintroll. She very rarely gets cross and takes even the most distressing circumstances (such as the arrival of a comet, or being washed away by a flood) in her stride. Moominmamma would permit anything to her child and his friends, even smoking (she says it's good for the stomach). Moominmamma is almost never without her handbag, which contains essentials like woolly socks, tummy powder, and bark. She makes bark boats every summer, and the first one goes to her favorite.
- Moominpappa (Muminpappan) - orphaned in his younger years, he is a somewhat restless soul who left the orphanage to venture out into the world in his youth but has now settled down, determined to be a responsible father to his family. He is almost always wearing his black top-hat, inside which is painted, "M.P. from your M.M." to differentiate it from all the other top hats in the world. Moominpappa also lived on a ship with three Hattifatteners for a few days, observing their behaviour.
- Sniff (Sniff) - Moomintroll's immature friend. He is a small animal of unknown species, though he somewhat resembles a brown rat or mouse. He is one of the few characters who is sincerely interested in money, and is always on the lookout for another way to get rich quick.
- Snufkin (Snusmumriken) - Moomintroll's best friend, who goes south every winter and returns in the spring. He is the son of the Mymble and the Joxter, and is half-brother to The Mymble's Daughter and Little My. Snufkin is an adventurer and a vagabond, admired by those who are small and shy. Snufkin wears old green clothes and a wide brimmed hat he's had since birth. He lives in a tent, smokes a pipe, and plays the harmonica. Snufkin also has a great dislike for The Park Keeper, and the many regulation signs and fences he puts up. At one point he sabotages The Park Keeper by planting Hattifatteners in his garden, causing them to grow and drive him out.
- Little My (Lilla My) - She is a small, determined and fiercely independent Mymble. When she wants something done, she does it straight away. She is very aggressive and totally disrespectful, but can be a good friend. She has a brash personality. She is Snufkin's half-sister and later Moomin's adopted sister.
- The Snork Maiden (Snorkfröken) - Moomintroll's fair lady friend and admirer. She does fall in love with others sometimes, but returns to Moomintroll before things get too serious. She has blonde hair and sports a golden anklet. She changes color according to her mood, with her baseline color in the books described as pale yellow.
- Snork (Snorken) - The Snork Maiden's brother, also friends with Moomintroll. He and his sister first meet Moomintroll in Comet in Moominland. He is described as mauve in colour, though changes to a pale green when frightened. His character is obsessing over details, rules and protocol in the books. In the 1990 TV series, he develops as an avid inventor, constructing crazy things including once a tricycle for Moominmamma's birthday.
- The Groke (Mårran) - She is cold and ghostlike, and represents loneliness and all that is scary in the world of Moomin. She seeks warmth and fire, but is unable to do anything but to put them out. Although she has a scary appearance and is dangerous to get close to due to the cold that she's radiating, she's not really evil... Just very lonely. Makes first appearance in Finn Family Moomintroll and returns in Moominland Midwinter and Moominpappa at Sea. The Groke is used for an exclamation, often like the word 'Lord'. ("The Groke knows...")
- Hemulens (Hemulen) Hemulens feature frequently in the books. One of them is an avid stamp collector, and another is an avid skier. A female Hemulen raised Moominpappa in an orphanage, and later Moominpappa met her aunt, who looked confusingly like her. Other characters frequently find the Hemulens annoying or overwhelming, as they can be somewhat loud, bossy, abrasive and insensitive, but they are well intentioned and usually have other redeeming qualities. In the beginning of Finn Family Moomintroll, a hemulen who is a keen stamp collector is depressed, as he has every stamp on the face of earth and has lost the purpose in life. Later on he finds a new purpose: to collect plants.
- Hattifatteners (Hattifnattar) - Small white ghost-like creatures that resemble worn socks. Hattifatteners are always on the move and travel in large groups (but always in odd numbers), such as boat convoys. Their only goal in life is to reach the horizon. During their travels they never say a word to each other, and it's doubtful that they have the ability to talk at all, they seem to communicate solely by telepathy -- except in the comics, where they complain bitterly to their host Moomin about the lack of food, cocktails and beds. The Hattifatteners cannot see very well, but their sense of touch is very strong, and they can feel ground vibrations and electricity. Hattifatteners assemble once a year when they "recharge" in a thunderstorm. At this time they should be avoided since they are highly charged and can give you electrical burns. Despite physiologically resembling animals, Hattifatteners grow from seeds. Planting Hattifattener seeds where someone has taken up residence is an effective way to get rid of him/her. Hattifatteners will only grow from this seed if it is sown on Midsummer Eve.
- Too-Ticky (Too-ticki) - A friend of the family, craftsman and practical philosopher. Has her first appearance in the novel Moominland Midwinter and returns in the short stories of Tales From Moominvalley and in comics. She is modelled after Tuulikki Pietilä, Tove Jansson's life partner.
- The Mymble (Mymlan) - Mother of Little My, Snufkin, and The Mymble's Daughter. She has many, many children, but is very jolly. She gets married to the Joxter in The Exploits of Moominpappa. The original Swedish word 'mymla' was a slang word used in Tove Jansson's circle, with the meaning "to love".
- The Mymble's Daughter (Mymlans dotter) - later known as simply The Mymble (Mymlan), she is the oldest of Mymble's many children. Every bit as independent as her youngest sibling, little My, Mymble's daughter is very proud of being the oldest sibling, and considers it her duty to raise Little My.
- Fillyjonk (Filifjonkan) - Known as The Fillyjonk in some English translations, the first we hear of is the late theatre director in Moominsummer Madness (Emma is his widow) and the young Fillyjonk who joins the Snork Maiden in the late night jaunt to the wishing well. Later we meet the wonderful psychological study of the Fillyjonk Who Believed In Disasters in Tales from Moominvalley. Not a single moment of fantasy or joy, only duties and discipline; she is an extremely methodical person tied down with principles and has a deep rooted belief in prestige and tradition. Nevertheless, after a catastrophe, The Fillyjonk can be freed from the trammels of social expectation and can discover the joys of freedom, irrationality and self-expression. Deep inside she has had a wish to live freely as the Moomin family does, without any worries.
- Ninny (Ninni) - Ninny first appears in "Tales from Moominvalley" in the story, "The Invisible Child". She turned invisible by being frightened too much by her former caretaker. This caretaker gave Ninny to Too-ticky, who then brought her to Moominmamma to help make Ninny visible again. Moominmamma succeeds with one of her granny's 'Infallible Household Remedies' and lots of love. Ninny at first is a bore and doesn't know how to play games or have fun. She becomes completely visible during a day on the beach. Moominpappa plans on sneaking up and scaring Moominmamma, but Ninny rushes up behind and shoves Moominpappa into the sea. In the end, the family realizes Ninny is very similar to Little My.
- Toffles (Knytt) - Toffles are small creatures, shy, scared and confused. A toffle called Salome is featured in Moominland Midwinter and a toffle only named as "Toffle" is the main character in Who Will Comfort Toffle?.
- The Hobgoblin (Trollkarlen) - Appearing in Finn Family Moomintroll, he is a powerful magician who travels the Universe with his flying panther, looking for the King's Ruby. His top hat is found in the Lonely Mountains by Moomintroll, Snufkin and Sniff, who take it back to Moominhouse. Chaos ensues, as anything you put inside the hat is transformed. Moomintroll himself is changed into a strange creature by the hat when he uses it to hide in during a game. The hat also changes the Moominhouse into a sort of jungle.
- Thingumy and Bob (Tofslan och Vifslan, with their English names likely owing to Edgar Allan Poe's Thingum Bob, Esq.) - Two little creatures who turn up in Moominvalley with a large suitcase, which contains the King's Ruby. They speak a strange language (with "-slan" appended to the ends of some words in the Swedish original, which became spoonerisms, e.g. :"'Man you cake it out?' asked Thingumy. 'Mot nutch,' said Bob", in the English translation) and are pursued by the Groke who wants the contents. They upset Moominmamma by stealing her handbag. They eventually return it and the whole family throws a party to celebrate. The Hobgoblin arrives when Thingumy and Bob open the suitcase, exposing the King's Ruby for all to see. While they didn't give him the ruby, when the Hobgoblin gave everyone there a wish they wished for the Hobgoblin to have a ruby as beautiful as theirs; the Queen's Ruby
- Stinky (Stinky) - A criminal by profession, trickster, and a dangerous influence who tempts the Moomin family to do things that are against the law. He has a code of conduct of his own, and is offended when the Moomins want to give him a large sum of money which has been causing them much trouble. Physically, Stinky looks like some sort of furry mammal, whose most characteristic attribute is his constant, unbearable stench. He appears in one book (An Unwanted Guest) but mainly in comics and cartoons.
- Niblings (Klippdassar) - small aquatic creatures, which chew off people's noses if they are too long for their taste. They enjoy doing the multiplication contests devised by the rather bossy Hemulen's Aunt. The Swedish word means rock hyrax.
- The Muskrat (Bisamråttan) - a philosopher who believes in the pointlessness of things and reads Spengler, appears in Comet in Moominland and Finn Family Moomintroll. The Moomin children annoy him by putting hairbrushes in his bed and such like. He eventually takes to living in the cave Sniff discovers in order to get some peace. There is an unfortunate accident, however: in Finn Family Moomintroll, Moomintroll has hidden the Hobgoblin's hat there; anything you put in the Hobgoblin's hat becomes transformed, and the Muskrat gets a nasty shock when he puts his false teeth in it to keep the sand out of them.
- Hodgkins (Fredrikson) - an inventor and childhood friend of Moominpappa (The Exploits of Moominpappa). He is Muddler's uncle. He builds the Oshun Oxtra (misspelling of Ocean Orchestra in English, known as Haffsårkestern in Swedish), a boat in which Moominpappa and his friends travel on their adventures.
- The Joxter (Joxaren) - Snufkin's father and childhood friend of Moominpappa (The Exploits of Moominpappa). He is very lazy and ends up marrying the Mymble.
- The Muddler (Rådd-djuret) - The nephew of Hodgkins and Sniff's father. A rather untidy and confused individual who collects buttons of all sorts and lives in the coffee tin where he keeps the buttons. Married to Fuzzy.
- The Fuzzy (Sås-djuret) - Sniff's mother. Married to Muddler.
- The Island Ghost (Spöket) - a spectre that haunts the Island colonised by Moominpappa in The Exploits of Moominpappa. He isn't very good at haunting and gets annoyed when the colonists laugh at him. He takes up knitting to soothe his nerves.
- The Ancestor (Förfadern) - the Moomintrolls descend from ancient creatures living in tiled stoves. One of those is still dwelling in the Moomin family's bathing house cupboard and stove. He is called the Ancestor and makes appearances in Moominland Midwinter and Moominvalley in November.
- Misabel (Misan) - a very depressed and paranoid female character. In comics and picture books, she is usually the Moomin family's domestic help. Misabel has her only novel appearance in Moominsummer Madness, in which she is not a domestic help, but shows up to be a good actress. She is sometimes the owner of Sorry-oo. It has been said that Misabel's initial reaction to anyone talking to her is fear of them complaining about the quality of her work.
- Whomper (Homsan) - an earnest little chap. He joins the Moomin family on the floating theater in "Moominsummer Madness".
- Emma (Teaterråttan Emma) - the rather bitter stage rat. She helps the Moomin family understand what a theater is and also collaborates with Moominpappa on his play, "The Lion's Brides".
- The Park Keeper (Parkvakten) - a Hemulen in charge of a park where the vegetation is trimmed and cut into proper lines and shapes. The park goes by very strict rules, mostly forbidding things, which are written out in big letters on several signs placed around the park. Of all the people in the world, the Park Keeper is the only one Snufkin really dislikes. Snufkin plants Hattifattener seeds in the grounds of the park to drive the Keeper away and then burns all the signs forbidding things.
- Sorry-oo (Ynk) - a small melancholic dog. He has his only novel appearance in Moominland Midwinter, in which he is constantly howling after his distant cousins the wolves.
- The Dweller Under the Sink (Den som bor under diskbänken) - a small, furry creature that lives under the sink in Moomin House. He only appears in Moominland Midwinter and becomes known to Moomintroll when he wakes up during the long winter hibernation undertaken by the whole Moominfamily. Moomintroll tries to strike up a conversation with him by complimenting on his rather bushy eyebrows, but only succeeds in upsetting him.
- Edward the Booble (Dronten Edward) - a gigantic monster (the second largest creature in the world - only his brother is larger) who pays for people's funerals if he accidentally treads on them. He is generally bad tempered because of this. He accidentally aids the launch of the Oshun Oxtra (Ocean Orchestra), a boat invented by Moominpappa's childhood friend, Hodgkins, by sitting in a river bed.
- Daddy Jones (Kungen/Självhärskaren) - the Autocrat in "Exploits". He owns a fairground full of surprises, sits on a throne and gives a blast on his foghorn when he makes royal proclamations.
- The Lady of the Cold (Isfrun) - a very creepy, beautiful lady who brings winter to Moominvalley. Looking into her eyes will turn you into a block of ice.
- Toft (Homsan Toft) - a small, very shy boy who appears in Moominvalley in November. Toft makes up one of the people visiting the Moomins while they are absent. He is very mysterious and seems to have the power to make things he imagines, come true. He is also able to use Moominpappa's crystal ball. In the original book, Toft is a whomper, but the English translator translated his character into a "boy".
- Grandpa Grumble (Onkelskruttet) - an old man who appears in Moominvalley in November. He is quite old and somewhat senile. He uses a cane and owns many pairs of glasses that he carries with him in a basket.
- Gaffsie (Gafsan) - not much is known about Gaffsie, except that she is a friend of Fillyjonk. She appears in Tales from Moominvalley in the stories "The Fillyjonk who Believed in Disasters," and also appears in the story "The Fir Tree." She is also mentioned in Moominvalley in November.
- The Witch (Häxan) - The Witch looks quite scary and has some powerful magic in her possession, but is a harmless old lady despite her strong dislike of the Moomins. She would prefer Alice not to play with them and pay more attention to her studies, but does warm up for them later on. (This character does not appear in the original stories or comics.)
- Alicia (Alisa) - Alice, the Witch's granddaughter, likes the Moomins and plays with them on the sly whenever the Witch is otherwise occupied. She is a witch-in-training herself, and develops several magic skills during the series, most notable walking on water, underwater breathing, and lightning speed. (This character does not appear in the original stories or comics.)
There are other characters who appear from time to time.
Several primary characters largely disappear from the later books in series. Most notable of these are Sniff and the Snork Maiden, who are after all members of the extended family and live with the Moomins in several books. But after The Exploits of Moominpappa, Sniff is suddenly and inexplicably no longer mentioned, and after Moominland Midwinter, the Snork Maiden, too, is absent from the stories. (They do not vanish completely, however, since Sniff later on plays a major role in both the short story Cedric in Tales from Moominvalley and in the picture-book The Dangerous Journey, the Snork Maiden is mentioned a few times in Moominpappa at Sea, and they both appear as minor characters in An Unwanted Guest.)