Queen Margaery Tyrell is the widow of King Renly Baratheon, a claimant to the Iron Throne in the War of the Five Kings. Her father Lord Mace Tyrell is the ruler of the Reach. She is betrothed to King Joffrey Baratheon after the Battle of Blackwater, and briefly becomes his queen, but this is cut short when Joffrey is fatally poisoned at their wedding feast. She has subsequently become betrothed to Joffrey's brother and successor, Tommen Baratheon. Margaery is known for her beauty, political cunning, and ambition, although she has a compassionate side.
Margaery is the only daughter of Lady Alerie Tyrell and Lord Mace Tyrell, the Lord Paramount of the Reach. The Reach is one of the constituent regions of the Seven Kingdoms and House Tyrell is one of the Great Houses of the realm. Margaery was raised in privilege in the family seat and regional capital of Highgarden. She is close to her brother, Ser Loras Tyrell, the Knight of Flowers. She is said to be as beautiful as she is clever.
Margaery marries King Renly Baratheon, the lover of her brother Loras, though she's aware of their relationship. Two weeks afterward they have not yet consummated their marriage. Renly camps his army in the Stormlands, near his seat of Storm's End, and holds a tournament for his followers. Margaery is disappointed when Loras is defeated in the final bout by Brienne of Tarth. Catelyn Stark arrives to treat with Renly on behalf of her son Robb Stark and Margaery greets her warmly. Margaery encourages Renly to produce an heir with her but he is unable to become aroused by her. She is pragmatic about his desires and shocks him by offering to bring Loras into their bed. King Joffrey Baratheon's Master of Coin Petyr "Littlefinger" Baelish also visits the camp to treat with Renly. He makes a point of provoking Margaery about her husband's sexuality and she affirms her loyalty to Renly. Renly treats with his brother King Stannis Baratheon but is unable to reach a compromise. Renly is killed in mysterious circumstances and his Kingsguard Brienne of Tarth is blamed for his death. Margaery convinces Loras to flee the camp with her before Stannis arrives. Littlefinger accompanies them to Highgarden having gauged Margaery's ambition to become Queen.
Petyr sways House Tyrell into siding with House Lannister. As a result, House Lannister is victorious at the Battle of the Blackwater.
In a ceremony to celebrate victory, King Joffrey tells Loras he may ask anything of him in return for his aid. He asks Joffrey wed Margaery to cement the new alliance between their Houses through matrimony. Margaery states she has heard of Joffrey's courage and come to love from afar. Joffrey states that he has heard of Margaery's beauty and reciprocates her feelings but balks at setting aside his betrothal to Sansa Stark but is convinced by his courtiers that Sansa's family's status as attainted traitors is reason enough.
Lady Margaery Tyrell accompanied her betrothed King Joffrey back from the Great Sept of Baelor in a heavily guarded palanquin. Against official protocol, she stopped the procession in Flea Bottom unexpectedly. To the shock of her guards and the bewilderment of Joffrey, Margaery stepped out of her carriage and began exploring the streets. She eventually arrived at an orphanage and began interacting with the children. Meanwhile, her servants distributed bread and toys, earning her the love of Flea Bottom's smallfolk. That evening, Margaery and her brother Loras Tyrell were visited by Joffrey and his mother Cersei. Cersei was unhappy with Margaery's earlier actions and admonished her boldness; reminding her that her impromptu charity work took place on the same streets where the royal party was assaulted weeks earlier. During this argument, Joffrey defended Margaery and criticized his mother. As a result, Cersei realized that she was on the verge of being outmaneuvered by the Tyrells. While Cersei only knew how to rule through fear, Margaery was adept at winning the hearts and minds of her people, a skill which Cersei lacked. Later, Margaery and her grandmother, Lady Olenna Tyrell, invited Sansa for a private meeting with them at the gardens of King’s Landing. Loras escorted Sansa to the gardens for the meeting. During the meeting, Lady Olenna dismissed her father Mace as a fool for supporting Renly Baratheon's claim to the throne. By contrast, Margaery spoke well of her late husband Renly. During the meeting, Olenna insisted that Sansa tell them the truth about what Joffrey was like since Margaery was to marry him. While Sansa was initially reluctant to share her feelings, she admitted that Joffrey was a "monster" since he had reneged on his earlier promise to spare her father’s life.
While Olenna was disappointed at these revelations, she was not surprised given the rumors that have been circulating about Joffrey's public outbursts. While Sansa was worried that this would mean that the Tyrells would cancel their proposed marriage alliance (meaning Sansa will be stuck with Joffrey again), Olenna assured her that her son Mace was too intent on Margaery entering into a royal marriage to cancel it for anything. Later, Joffrey gave Margaery a tour of the Great Sept of Baelor, where their royal wedding was scheduled to be held. They were followed by Cersei Lannister and Olenna Tyrell, representing the Lannisters and Tyrells respectively. During their tour, Joffrey talked about the various Targaryen kings who were buried within the Great Sept. Margaery feigned interest in Joffrey's topic but his mother Cersei was annoyed. While Cersei and Olenna were engrossed in a conversation about the men in their lifes, Margaery managed to convince Joffrey to greet the crowd outside. Having been somewhat placated by Margaery's charity, the crowd happily cheered for the pair. As a result of this incident, Cersei felt that she had lost control of Joffrey to the Tyrells. She came to fear that the Tyrells did not have her family’s interest at heart. In response, the Queen Regent ordered Petyr "Littlefinger" Baelish to spy on the Tyrells. Later, Ser Loras invited Margaery and Sansa to watch him sparring him with squire at the castle gardens. During that time, Sansa praised Loras' swordsmanship and expressed her interest in marrying Loras as part of the Tyrell plot to keep her out of the hands of Baelish and/or the Lannisters. Margaery replied that she would "plant the seed" of the idea after she and Joffrey got married. While Sansa was sceptical that Joffrey would let her go, Margaery was confident that he would do it to please his betrothed. Unknown to Margaery and Sansa, Ser Loras was having a secret homosexual relationship with his squire Olyvar. During this meeting, Loras briefly mentioned that he was to be married to Sansa. Unknown to Loras, Olyvar was a spy working for Littlefinger, who reported to Cersei. In response, Cersei's father Lord Tywin Lannister arranged for Cersei and her brother Tyrion Lannister to marry Loras and Sansa respectively in order to curb the ambitions of House Tyrell and to bolster the marriage alliance between the Lannisters and the Tyrells. While Sansa was unhappy about this arranged marriage to a Lannister, Maragery Tyrell consoled Sansa by reminding her that Tyrion was far from the worst Lannister and that Tyrion might be able to make her happy given his skills as a lover. Later, Margaery also attended Sansa and Tyrion's wedding. Prior to the wedding reception, she attempted to ingratiate herself with Cersei, commenting that they would technically be sisters soon. However, Cersei rebuffed her friendship by telling Margaery about the story behind the "Rains of Castamere". She explained that the song referred to House Lannister's destruction of the rebellious of House Reyne of Castamere. This was meant to infer similarities between the ambitions and position of Houses Reyne and Tyrell and that the same fate may fall upon House Tyrell if they plotted against the Lannisters). Cersei also threatened to have Margaery strangled in her sleep if she ever dared to call Cersei sister again. During the wedding dinner, Margaery was seated with her grandmother Olenna and the two talked about the dynamics of the Lannister and Tyrell families, with Margaery shooting her grandmother a withering glare when Loras stormed out.
Olenna assists Margaery in picking out a necklace for her upcoming wedding. She selects the finest of those on offer, noting affectionately that it is similar to one she received from Margaery's grandfather on her 51st name day. Olenna chucks the piece over the rampart and into Blackwater Bay and orders the Tyrell handmaidens to canvass every jeweler in King's Landing for better offerings. After they are left alone, Margaery sardonically suggests letting Joffrey pick out the necklace, which knowing him will likely consist of severed sparrow's heads. Olenna cautions Margaery to mind what she says, even with her. They are shortly interrupted by Brienne of Tarth, who has come to speak with Margaery about Renly's death. In private, Brienne explains what she saw and how the shadow had Stannis's face, and assures Margaery that she will find a way to avenge their king. Margaery reminds Brienne that Joffrey is their king now. Brienne apologizes for any offense given, but Margaery assures her that none was taken. Margaery's wedding to Joffrey goes off without a hitch. At the wedding feast, however, Joffrey's cruelty and twisted sense of humor become apparent in the tasteless performance of the War of the Five Kings he has performed and in his treatment of his uncle Tyrion. Margaery is only barely able to distract him, proving her control over him is fleeting. Everything is cut short, however, when Joffrey is poisoned and dies in front of Margaery's eyes.
As the capital is in "mourning", Margaery inquires to Olenna if she is actually the queen or not. Her grandmother advises her to not press the issue just yet. She tells Margaery of how she felt when Luthor Tyrell died, but also says that Margaery is at least lucky that her third marriage should be easier than the other two. Margaery is surprised by this, but Olenna points out that the Lannisters need their alliance with the Tyrells far more than they do.
Margaery learns, to her disappointment, that Olenna intends to return to Highgarden before Tommen's coronation. Her grandmother tells her that she should be able to handle things herself from this point. Before she leaves, Olenna tells her about how she seduced Luthor Tyrell to get out of her engagement to a Targaryen, and advises Margaery to make her move on Tommen while Cersei is still distracted over Joffrey's murder. Margaery is confused by Olenna's certainty that Tyrion is innocent, until Olenna makes it clear that she would never have allowed Margaery to marry "that beast", heavily implying that it was she who poisoned Joffrey. Later that night, Margaery steals into Tommen's bedchamber, apparently easily sneaking past the Kingsguard. She discusses rumors of their upcoming wedding with him and interacts in a friendly manner with his cat, Ser Pounce. Margaery and Tommen bond over their relief that they won't have to live in fear of Joffrey anymore. Margaery asks if she can visit him again in secret; Tommen agrees. Realizing that she must be maternal in her initial manipulation of him, Margaery gives him a kiss on the forehead as she leaves.
Still dressed in mourning clothes, Margaery watches Tommen's coronation from the side gallery of the great hall. Cersei approaches her and engages her in conversation. To Margaery's surprise, Cersei says that the things Joffrey did shocked her, then asks rhetorically if Margaery thinks many things shock her. Cersei asks if Margaery still wants to be the queen, to which the lady replies that she hasn't thought about it. Cersei ignores the obvious lie and says that Tommen will need someone to guide him; apparently, she doesn't have the will to fight about Margaery being that someone anymore. Cersei and Tywin later set the date of Margaery and Tommen's wedding to right after the mourning period is over, a fortnight from the coronation.
Along with her brother and father (who is one of the three judges), Margaery is present at the trial of Tyrion Lannister. Although she isn't particularly fond of Tyrion, she looks visibly displeased at the proceedings, well aware that Tyrion is innocent and the trial is a farce. Nonetheless, Margaery remains silent throughout the trial.
Margaery, along with lords and ladies from all over the Seven Kingdoms, stands on the Great Sept of Baelor as Cersei Lannister arrives to mourn the loss of her father. During the reception at the Red Keep afterwards, Cersei notices her exchanging a few close words with Tommen and holding his hand briefly. Later on, Margaery interrupts Loras as he is abed with Olyvar. Irritated at her brother's lack of discretion, she dismisses Olyvar. Loras is puzzled by Margaery's relaxed attitude, as Tywin's death means Cersei won't be forced to marry Loras and be sent off with him to Highgarden, which means Margaery will have to contend with her mother-in-law at the capital. Margaery implies that may not be the case.
Tommen and Margaery are finally wed, much to the dismay of Cersei. That night, they consummate their marriage. They are elated and discuss their future together. Tommen tells Margaery how he thinks that his mother is unhappy in King's Landing. Seeing an opportunity to get rid of Cersei, Margaery manipulates Tommen into thinking that as long as Cersei stays in King’s Landing, she will continue to treat him like a child, like a mother lioness watching over her cub. When Tommen tries to convince his mother to leave King's Landing, Cersei deduces that this is Margaery’s doing and pays her a visit, only to find Margaery busy gloating about her “exhausting” night with the King. Greeting her new mother-in-law, Margaery, now more confident than ever and even dressing like Cersei, rubs her queenship and marriage in Cersei’s face, getting less subtle with each barb. Seeing herself losing, Cersei walks away.
Later, however, Margaery becomes angry when her brother is arrested by the Faith Militant. She confronts Tommen, who eventually claims that his mother was not responsible and there was no way to free Loras without bloodshed, but Margaery, who has much more court and political experience than Tommen, is perfectly aware that Cersei played a role in her brother's arrest in order to divide her and Tommen. She subsequently decides to write to Olenna for help.
Olenna arrives shortly after and speaks with Margaery, sharing her belief that even though the Faith Militant arrested Loras, Cersei was the true mastermind. Later, at Loras's Holy Inquest, Margaery is called to testify and she backs her brother's denial towards the charges against him. However, Olyvar is called in to give testimony, though it is clear he has been instructed by Cersei. He confirms the accusations against Loras, who is to be put on trial. Margaery, to her horror, is also arrested by the High Sparrow for giving false testimony, and dragged from the room while calling Tommen for help.
Margaery is placed in a cell beneath the Sept of Baelor. Cersei comes to visit her, bringing her dinner and offering her condolences, but by now, Margaery knows of Cersei's part in the plan to have her and Loras arrested, accuses her of lying and ultimately orders her to leave, throwing the bowl of stew at her and calling her a "hateful bitch". The High Sparrow later tells Cersei that both Margaery and Loras are to stand trial.
Still in her dank cell, a bruised Margaery is being read to ceaslessly from the Seven Pointed Star regarding sin by Septa Unella. Margaery inquires about Loras' condition, but Unella says she must confess her sins first. When the Queen demands to know how her brother is doing the septa moves to strike her, much to Margaery's horror. At that precise moment the High Sparrow steps in and stops Unella, ordering his acolyte to attend the Faith's 'other guests'. His High Holiness admits that at times Unella takes her devotion too far, still Margaery's questions concerning Loras remain unanswered. Instead the High Septon offers that Tommen misses his wife terribly, and that the love between husband and wife is sacrosanct. Sins however have a way of leading decent people away from all things sacred, and into wickedness. Margaery claims she has committed no sins. The High Sparrow gently reprimands the Tyrell Queen, asking if she considers herself to be "wholly without sin"? When Margaery at last admits that no one is perfect, and everyone makes mistakes, the High Sparrow assures her she's on the right path, but has many miles left to go.
Some time later, Margaery is again brought to speak with the High Sparrow. He relates his story about how he began to reject the material world, but Margaery calls him out for quoting from the Book of the Stranger. She admits she isn't that familiar with The Seven-Pointed Star, but Septa Unella has been reading passages from it at her. The High Sparrow agrees that Unella has a habit of reading at people and finishes his story, and allows Margaery to see Loras. Seeing that he has nearly given up hope, Margaery encourages him to keep fighting.
Eventually, the High Sparrow allows Tommen to visit Margaery, who confesses to him her newly found devotion to the Faith. She admits that though she had always put on a kind and caring persona in the past, she did so with ulterior motives. Upon being asked by Tommen of Loras, she states that he must atone for his sins. Just before her own walk of atonement on the steps of the Great Sept of Baelor, her Father, along with his army and Jaime Lannister arrive in order to prevent her humiliation from happening. Jaime threatens to incapacitate the Faith Militant by force, but before any hostility can occur, the High Sparrow announces King Tommen as a newly converted follower of the Faith and calls off Margaery's atonement, claiming that she has done her part by bringing Tommen onto their side.
Under the supervision of Septa Unella, Margaery meets with Olenna inside the Red Keep. Olenna openly insults Septa Unella, who Margaery defends, saying she has been a true friend and teacher. Olenna reacts with disgust, pulling Margaery into another room in an attempt to have some privacy. Septa Unella follows them. Olenna begins verbally attacking Septa Unella, stating that she needs a good bashing. Once more, Margaery comes to the Septa's defense. Olenna questions what the Sparrows have done to her, and Margaery replies that Olenna marched against the gods. Olenna argues that they marched for Margaery and Loras' sake. Margaery replies that the gods could have punished Olenna and her allies for their blasphemy, but they instead showed mercy. Olenna reminds Margaery that Loras is still imprisoned and that that is hardly mercy. Margaery assures her that Loras may return to Highgarden following his atonement, though he will have to renounce his titles and live the rest of his life in penitance. Olenna is rightfully horrified by this due to the fact that Loras is the heir to Highgarden and believing that Margaery's loyalties towards her family and house have weakened. Before she can say more, Margaery kneels in front of her and urges her to return to Highgarden. Olenna says that she will never leave Margaery.
Margaery repeats her plea, secretly slipping a piece of paper into her grandmother's hand. Understanding the silent message, Olenna relents. She tells Margaery that she will see her soon, and the two share a hug. During the hug, Margaery's mask slips for a split second because of the emotion. After Olenna leaves, Margaery cheerfully asks Septa Unella if she would like to pray. Outside the room, Olenna unfolds the note to find a rose—House Tyrell's sigil—drawn on it. This reassures her that Margaery's true loyalty remains with the family.
On the day of Cersei and Loras's trial, Margaery stands with her father in the Great Sept of Baelor, and watches from the sidelines as Loras renounces his allegiance to House Tyrell and confesses to his accusations. She comforts her father and restrains him from intervening when the Faith militant begin carving the seven-pointed star into Loras's forehead. When Cersei does not show up for her own trial, the High Sparrow sends Lancel Lannister to bring her to the sept by force, and after Lancel himself does not return after a prolonged period of time, Margaery suggests to the High Sparrow that Cersei has a plan and is plotting against them, urging him to evacuate everyone before it is too late. Clearly underestimating Cersei, the High Sparrow dismisses this notion and has his Sparrows keep the Tyrell siblings from leaving the sept, along with everyone else present.
Powerless to do anything, Margaery clutches her brother as the sept erupts in an explosion of green wildfire, killing everyone inside, including Margaery, Loras, and their father. As a result of Margaery's death, Tommen committs suicide after he sees the burning sept from his chambers in the Red Keep.
Lady Olenna later meets with Ellaria Sand to discuss a new pact between Dorne and House Tyrell, mourning the death of her son and grandchildren. Ellaria promises her vengeance in the form of an allegiance with Daenerys Targaryen.
Mace Tyrell's only daughter, Margaery, was a clever as she was beautiful. Widowed by both Renly Baratheon and King Joffrey, she married Joffrey's brother, Tommen, in an effort to maintain an alliance between the Tyrells and the Lannisters. She was taken into custody for bearing false witness before the gods when she lied to defend her brother Loras against accusations of perversion. After forming a relationship with the High Sparrow, Margaery persuaded her husband to accept an alliance between the Crown and the Faith. She later convinced her brother Loras to confess his crimes and swear off his inheritance at his trial in exchange for his freedom. She was among those killed when the Sept of Baelor exploded.
Margaery's beauty is equivalent to her cleverness, both of which she has in abundance. A true protegè of her grandmother Olenna, she is a gifted manipulator who know how to maneuver her way in court politics. Margaery's strength is in her ability to win the minds and loyalties of her subjects, which has proven to be a threat to those who rival her family such as the Lannisters. She demonstrated her formidable skill in her charity work and manipulation of Joffrey; making him think she was excited by his dark impulses. In return Margaery gained the acceptance of both her subjects and Joffrey , who was an unpredictable and uncontrollable madman to everyone else, including his mother. This proved to be a threat to Cersei, who only relied on the fear of her family name and her position as a source of power.
Margaery possesses the tact and politeness that Cersei lacks. While Cersei is blunt and often rude, Margaery is capable of exuding the courtly behavior and courtesies expected of a queen - while still privately engaging in palace intrigues to increase her family's power. Cersei scorns her status as a woman in a realm dominated by men, though she is willing to use sex as a weapon to seduce those she needs (such as her cousin Lancel). In contrast, Margaery works within the social standards of "proper" femininity in Westeros, but adeptly turns them to her favor, to orchestrate political machinations from behind the scenes.
Although Margaery has had to develop many different facades depending on who she is trying to manipulate, she is shown to genuinely have a good heart, compassion, and empathy. Margaery has loving relationships with all of her family members. She loves her brother Loras and is entirely tolerant of his homosexuality - to the point that when her father contracted a marriage-alliance between herself and Loras's own lover Renly, she acknowledged that it was a paper marriage, and was quite frank that she had no issues with her new husband continuing his sexual relationship with her brother.