Molly Weasley is a plump, red-haired witch who is mother to Ron and his siblings (Bill, Charlie, Percy, Fred, George and Ginny). She is kind and even motherly to Harry, but can be stern and strict with her own children.
Molly comes to Hogwarts with Arthur when Ginny is taken into the Chamber of Secrets. She is weeping in Professor McGonagall’s office when Harry and Ron appear with Ginny alive and well. She is overjoyed to see Ginny and sweeps her and then Ron and Harry into a tight hug.
Molly writes to Vernon and Petunia Dursley during the school holidays, asking permission to take Harry to the Quidditch World Cup. She tells the Dursleys that they would be happy for Harry to stay at The Burrow for the remainder of the summer holidays, and that they will make sure he gets back to school safely in September. She is unsure about sending post the Muggle way, and covers the whole envelope in stamps to make sure it will arrive safely.
Molly overhears Arthur telling off Fred and George, and wants to know what they have done 'this time'. She suspects that it has something to do with Weasleys' Wizard Wheezes.
Earlier in the summer, Molly discovered a stack of order forms for joke products they had invented, whilst she was cleaning Fred and George's room. She was furious about their plans, burning the order forms and forbidding them from making any more products. She was disappointed in the twins' exam results, as they didn't get as many Ordinary Wizarding Levels (O.W.Ls) as she had expected. Molly wants the twins to eventually work at the Ministry of Magic like their father, and was angry when they told her that all they want to do is open a joke shop.
Based on the shouts heard coming from the kitchen at The Burrow, Molly is furious when she hears about Fred's practical joke on Dudley Dursley. When Harry and Ron return to the kitchen, Molly looks extremely bad-tempered. Using her wand a little more vigorously than usual, she causes the pile of potatoes in the sink to shoot out of their skins so fast that they ricochet off the walls and the ceiling. She rants about the twins as she prepares dinner, distressed about their lack of academic ambition. Although she knows that the twins are intelligent, Molly believes they are wasting their abilities on practical jokes and tricks; she thinks that they will end up in front of the Improper Use of Magic Office if they are not careful. She becomes more irritated when she picks up what she believes to be her wand from the kitchen table, only for it to emit a loud squeak and turn into a giant rubber mouse–another joke product made by Fred and George.
Molly prepares a delicious dinner for everyone at The Burrow. During the meal she attempts to persuade Bill to let her trim his hair, as she doesn't like how long it has grown, and wonders what those at Gringotts think about his dangling fang earring. At the end of the meal she ushers everyone to bed, conscious of the time, as some of them have to be up at the crack of dawn the next day.
Molly wakes Harry, Ron and the twins early in the morning. She is not attending the Quidditch World Cup, but makes breakfast for those travelling by Portkey. She leaves the kitchen to hurry Hermione and Ginny, irritated by Fred and George's grumbling. Molly is furious when she notices that George has Ton-Tongue Toffees hidden in his pocket, having told the twins to destroy the sweets. She summons all the hidden sweets from the twins' clothes, angry that they were trying to smuggle them out of the house.
Molly is relieved when the group return to The Burrow, and has evidently been waiting for them in the front yard for a while. She runs towards them, still wearing her bedroom slippers, her face pale and strained, a screwed up copy of the Daily Prophet in her hands. She flings her arms around Arthur, dropping the Daily Prophet onto the ground, and tells them that she has been so worried about them all. She seizes Fred and George, pulling them into a tight hug, horrified that the last thing she had done before they left was shout at the twins.
In the kitchen, Molly is handed a cup of very strong tea, with a shot of Ogdens Old Firewhisky added by Arthur. She is upset when Arthur insists on going into work almost as soon as he reads the Daily Prophet article. She tells the boys later that Arthur hasn't had to go into work on a weekend since the days of You-Know-Who; she thinks they are working Arthur far too hard.
Molly went to Diagon Alley whilst the rest of the family were at the Quidditch World Cup, and bought Harry, Ron and Hermione their school supplies whilst she was there. She enters Ron's bedroom as he and Harry are packing their things for school. She tells Ron that the thing he found whilst packing that he mistakes for Ginny's dress are actually his dress robes, which he needs for school. She tells Harry to open his dress robes, saying she thought the bottle-green colour would bring out the colour of his eyes. She looks embarassed when Ron asks why he couldn't have had new robes like Harry, and tells him that as his were bought second-hand, there wasn't much choice. She leaves the bedroom in a huff when Ron says he won't wear the robes.
Molly braves the telephone in the village Post Office to order three Muggle taxis to take everyone to Kings Cross Station. She tells Harry that Arthur tried to borrow Ministry cars for the journey, as they had done in Harry's second year, but there were none available. As she says goodbye to Harry and Hermione, she tells them that she won't be inviting them for Christmas this year, as she thinks they will all want to stay at Hogwarts. She refuses to tell them what she means, but hints that they are gong to have a very exciting year. She mentions that she is glad the rules have been changed, but won't tell them anything more.
Charlie tells Hagrid that Molly is frantically worried about Harry being chosen as a champion for the Triwizard Tournament. She was in floods of tears after the article in the Daily Prophet was published, upset by the news that Harry still cries about his parents.
Molly sends Harry, Ron and Hermione chocolate eggs for Easter. Harry and Ron's are the size of dragon eggs, and are full of home-made toffee, whilst Hermione's egg is smaller than a chicken's. According to Ron, Molly subscribes to Witch Weekly for the recipes, and thus probably read Rita Skeeter's article about Hermione supposedly breaking Harry's heart.
Molly visits Hogwarts with Bill on the morning of the third task. She and Bill wait with the families of the other Triwizard champions, happy to stand in for Harry's own family. She is annoyed when Amos Diggory makes remarks about Cedric beating Harry, knowing that the influence of Rita Skeeter's article is affecting his opinion of the boy. Molly and Bill spend the morning walking the castle grounds with Harry, seeing both the Beauxbatons carriage and the Durmstrang ship. She is particularly intrigued by the Whomping Willow, which was planted after she left Hogwarts, and reminisces at length about her time at Hogwarts. The three are joined for lunch by Ron, the twins, Ginny and Hermione. Molly greets Hermione much more stiffly than usual, but denies ever believing any of the gossip in Rita Skeeter's articles when Harry tells her it was not true. She is considerably warmer towards Hermione from then on. Molly, Bill and Harry while the afternoon away with a long walk around the castle, returning to the Great Hall for the evening feast. After the meal, Molly makes her way to the Quidditch pitch with the other spectators to watch the third task.
Mrs Weasley stands in the hospital wing with Bill, Ron and Hermione, grouped around Madam Pomfrey. They appear to be demanding to know where Harry is, and what has happened to him. When Molly catches sight of Harry and Professor Dumbledore in the doorway, she lets out a kind of muffled scream, and starts to hurry towards him. She is prevented from reaching Harry by Professor Dumbledore, and nods as the headmaster asks the group to let Harry rest in quiet. She rounds on Ron, Hermione and Bill as though they are being noisy and tells them to keep quiet.
After the confrontation with Cornelius Fudge in the hospital wing, Molly tells Dumbledore that he can count on her and Arthur's support. She screams when Sirius Black transforms back from his Animagus form, horrified that the supposed criminal is at Hogwarts. After Dumbledore gives his instructions to those in the hospital wing, Molly encourages Harry to take the rest of his potion, and to sleep. She tells Harry that Cedric's death wasn't his fault, and hugs the boy tightly.
Molly is waiting for the children at Kings Cross Station when the Hogwarts Express arrives. She hugs Harry very tightly when she sees him, and tells him that she thinks Dumbledore will let him stay with the Weasleys later in the summer.
Mrs Weasley greets Harry with a rib-cracking hug when he enters number twelve, Grimmauld Place. She looks rather thinner and paler than she did at the Triwizard Tournament, but beams as she walks towards him. She speaks in a whisper, directing the members of the Advance Guard to a room off the hallway, where a meeting of the Order of the Phoenix has just begun, and leads Harry up the stairs to his room on the second floor of the house. She tells Harry that the meeting is for Order members only, and that he will have to wait with Ron and Hermione until it is over. The twins reveal that Mrs Weasley was furious when she discovered they were using Extendable Ears to listen in on the Order meetings. She has begun placing an Imperturbable Charm around the meeting room door to prevent the Ears from being used.
The Weasley children reveal that during Percy's row with their father, he accused Arthur and Molly of becoming traitors to the Ministry. Molly has been in a terrible state ever since the argument. She came to London to try to talk to Percy but he slammed the door in her face.
Mrs Weasley walks up to the second floor bedroom after the Order meeting finishes to fetch the children for dinner. She wants to know why there are a group of Dungbombs outside the meeting room door, unaware that Ginny was throwing them at the door to check for the presence of an Imperturbable Charm. Once the other Order members have left the house, she, Lupin and Tonks magically seal the many locks and bolts on the front door. Molly is frustrated when Tonks knocks over the umbrella stand in the hallway and wakes the portrait of Mrs Black, which in turns wakes the rest of the portraits in the hallway. Molly and Remus Lupin dart forward to close the curtains around Mrs Black's portrait, but Molly soon abandons the attempt to hurry down the hall and Stun the other portraits with her wand.
Along with the other members of the house, Mrs Weasley attempts to rid the drawing room at number twelve, Grimmauld Place of its infestation of Doxys. She also found a nest of dead Puffskeins under the sofa. She looks rather peculiar with a cloth tied around her nose and mouth, and is holding a large bottle of Doxycide. When Sirius arrives to help get rid of a suspected Boggart, Molly speaks in a carefully polite voice, not having forgotten their disagreement the night before. Molly is furious when Mundungus Fletcher arrives in the house with a collection of stolen cauldrons. She shouts at the wizard, having been looking for an excuse to tell him off every since he abandoned his watch in Little Whinging, leaving Harry in danger. Molly and Sirius are cousins by marriage.
Over the next three days, Molly keeps those at Grimmauld Place working hard to decontaminate the drawing room. They then move their attentions to the dining room on the ground floor, helped occasionally by visitors to the house. Molly irons Harry's best clothes in preparation for the hearing, keen for him to make a good impression on the Ministry officials. She agrees with Professor Dumbledore that Sirius should not accompany Harry to the hearing, much to Sirius's disgust.
Molly lays out clean jeans and a t-shirt for Harry to wear to his hearing. She stands in the kitchen making breakfast, dressed in a quilted purple dressing gown, when Harry appears downstairs. She hugs Harry as he and Arthur prepare to leave for the Ministry of Magic, and tells him that they all have their fingers crossed for him.
Molly and Arthur visit Weasleys' Wizard Wheezes along with Harry, Ron, Hermione and Ginny. Molly is horrified by the controversial U-NO-POO sign in the shop window, certain that the twins will get into trouble. She spends time with Ginny admiring the tiny Pygmy Puffs in their cage.