In 1862, young English widow Anna Owens accepts the job of teaching the royal children of Siam. On her arrival in Bangkok, culture clash is immediate. The king respects Anna for standing up to him, though this appalls his courtiers. In due course, she becomes the king’s confidant and diplomatic advisor; their relationship endures through many trials.
An opening crawl states that in the Victorian era of the early 1860s a young Englishwoman accepted the post of teaching English to the children of the King of Siam that strange and still half-barbaric country.Anna Owens (Irene Dunn), a proper widowed Englishwoman arrives by boat in Siam with her son Louis and her servants. She talks with the boat's captain about the country. He tells her the King's palace is known as the Universe, a single Sun with a thousand moons – the sun being the King and the moons being his many women, including a harem. Chow Koon (Lee J. Cobb), the Prime Minister, arrives at the dock to meet her and through his translator, asks her about her late husband and what he did. She tells him his only concern should be with her capacity as governess. His translator tells her she will be taken to the palace. She argues that she was promised a house of her own upon her arrival. He responds if she won't go to the palace, she can go wherever she pleases. Then they simply leave. Anna is offended and says he was rude, but the Captain explains that in Siam they ask personal questions to be polite. And the fact that he came to meet her in person was a sign of respect – women "do not exist" in this country. He suggests she tells him she didn't understand and apologize to him in the morning.She stays the night on the boat and arrives on foot at the palace the next morning, politely asking to see the Minister. She apologizes for her behavior the night before. He asks through the translator if she is really sorry or just being polite to ask for a favor. She admits it's both – she needs his help to get started in her job. Her son Louis comments that he's not wearing a coat and that he's afraid of him. Chow Koon laughs and begins talking to them in English. He admits he likes the boy and acts more friendly. He asks why she cannot live in the palace instead of having her own house. She replies that she needs time alone with her son after her duties are done. Chow believes that the King promised her a house, but says the King does not always remember his promises, and that if he reminds him it might make His Majesty angry. Anna says she will be glad to tell the King about it herself. The Minister tells her the King's busy schedule and that she might have to wait for days to see him. He will arrange the meeting, and comments it should be very interesting.She begins to unpack in the palace and her female servant is concerned that she was told her husband Moonshe cannot stay with her. When Anna tries to leave for dinner, there are female guards blocking the door. She discovers she is being housed in the harem of the palace.A month or so passes and the day of her meeting with the King finally arrives. Chow Koon has her shown the method of greeting the King – descending on the floor and then crawling on her hands and knees. Anna refuses and shows him how she and her son will bow. He tells her she can do what she wishes, but remember she is not the only one with a temper. After waiting for a time she is brought in, only to be told the King will not have time to see her. She refuses to wait and barges up to him along with Louis. "Who, Who, Who?" asks the irritated King (Rex Harrison) upon seeing her. She is announced as the governess. He says she does not look like a scientific person to teach a school and asks her how old she is, so she responds 150. He tries to challenge her on that comment with other questions like when she was born and how long she's been married. Finally he stumps her by asking how many grandchildren she has, which she cannot think up a quick answer to. "I make better questions that you make answers", he laughs, almost like an amused child. He asks if she is not afraid to tell him something is not his business. She says it would not be a compliment to His Majesty to be afraid of him. Not being afraid is good in a scientific mind, he agrees. He is pleased and brings her into another chamber to meet his wives and children – he has several wives and 67 children in all. He tells her to begin teaching his children and any of his wives who have sense to learn on the next Thursday. Then he asks Chow Koon why she was not presented to him sooner!The next day as she prepares for school, the king arrives upset. He complains that the newspaper called him a spare man, but he insists he is very necessary. She explains that spare has two meanings – one is thin. Instead of being relieved, he is upset that a woman has corrected him. "How can King be wrong and woman be right?" he chides. He decides to cancel the class, so she instead asks about the house he promised her. He tells her she is just a slave and it is his pleasure that she resides in the palace. She storms off, even as he angrily tells her to come back. She packs to leave, only to have one of the King's men arrive and tell her that the King has decided to give her a house. But the place she is taken to is little more than a run-down shack. She refuses it, but she decides to stay in Siam anyway, insisting he will give her a real house before she leaves if she has to stay there the rest of her life!She starts teaching the children the next day with the help of Lady Thiang (Gale Sondergaard), a woman who learned English from missionaries. A month passes, and as the king examines his daily assortment of gifts, one of them turns out to be a beautiful young woman named Tuptim, (Linda Darnell) a gift from the governor of Lao Province. He also finds a model of a house marked "Made in England" with the inscription "A man's house is only less dear to him than his honor." He also finds that his children are learning sayings like "A promise deferred is justice delayed", and Miss Owens is teaching them to sing, "There's no place like home."Later, his Prime Minister tells him they have lost Cambodia. France has made a treaty with the country and declared it independent of Siam and under their protection. The King realizes that outside forces are trying to break up his country, but he does not wish to fight; he wants to hold the country together and keep what is left safe. Chow Koon laments that he never should have asked his friend to leave the monastery he was living in and become King. He wonders what they should do. When the King hears "Home, Sweet Home" being played again he tell his minister thats a sign to never give up on anything. He orders Chow Koon to find Anna a house.The house the governess is given now is much nicer and she is pleased with it. But she tells Chow Koon that now that she has been given the house she was promised, she is leaving. She won't stay in a country where promises mean nothing. She tries to leave for the boat, but Chow has her dragged away to his house. But there he asks her politely to stay. He tells her the King is two men – one a king, one a man trying to modernize his country quickly and being rejected by some of his people as he does so. The conflict between the two makes it hard to know how to act. He says someone like her is needed because she can speak to the King both as a woman and someone he respects, and he will listen to her because she is not trying to gain his favor. Anna is touched by his concern and agrees to stay.At a class later on, Tuptim arrives with a monkey on her shoulder. Anna insists that she take the monkey away, threatening to report her to the king. She takes the monkey outside, but challenges her to report her anyway. Lady Thiang warns Anna that Tuptim is the King's new favorite now. The teacher later finds out that Lady Thiang is the mother of one of her best students – the King's eldest son Prince Chulalongkorn. When she goes to find Louis, she discovers he is having a disagreement with the prince, who heard him apologize to his mother and thought this was unmanly. Anna explains that she is like a father to Louis, and thus he does not resent being corrected by her just as the prince accepts criticism from his own father. The prince admits he is glad it is not like that is his country, but he respects Louis once again.One night, Anna is summoned by the King in the middle of the night. But he only called her to complain that he thinks Moses is a fool, because he said the world was created in only six days. While walking back to her house, she hears a baby crying and sees Lady Tuptim's slave chained to a post with her baby in her arms. Anna speaks to Tuptim the next day on the slaves behalf, explaining that the woman tried to buy her freedom and she does not understand why she refused to let her go – even though the law of Siam says she must. Tuptim is unhappy about her own situation so she does not see why her slave her slave should be allowed to be happy. Anna goes to the king to talk about it, but he has already heard about it from Tuptim and doesn't wish to be bothered. She explains that no one, even the King, is above the law – it must apply to all people, even if they are the King's favorite. Otherwise the word of the King would mean nothing and could be overturned by his successor. They talk about Queen Victoria and President Lincoln, but he will not comment any further on Tuptim's slave. However, the next morning, Tuptim shows Anna a gift the king gave her in exchange for freeing the slave. But when Anna lets it slip that she talked to the king, Tuptim realizes he gave her the gift at the teacher's suggestion. She feels she is no longer the King's favorite and angrily smashes the gift.Again Anna is summoned by the King, this time while eating lunch. Sir Edward Ramsey is coming to visit and His Majesty wants the Englishwoman to prepare his prettiest women for presentation in the European fashion, in order to have Ramsey report back to Queen Victoria that he is not a barbarian as other visitors to England have claimed that he is. She suggests that he set up consulates in his country so that other country can see for real what the Siamese are like, instead of hearing stories from sea captains and such. He rejects the idea, but then later summons her with the same suggestion, except he adds that they should all meet over dinner first. The dinner is held the following Saturday. The people are impressed with the King's knowledge of America and Abraham Lincoln. He tells them Siam is aware of what is happening all over the globe. Afterward, he has Anna summoned late that night. He is eating now and tells her he was too nervous and afraid to eat at the dinner, but feels fine now that everything has gone well. He gives her a gift as a reward, and shares his meal with her.At class the next day, no one is there. Curious, Anna asks Lady Thiang what is happening. Lady Thiang tells her that Lady Tuptim had escaped from the palace but has been recaptured fleeing from a monastery along with a young man. She says her trial is already taking place, and Anna goes to help her. At the trial (which is more of an inquest), Tuptim tries to explain that the young monk is indeed a young man she was once betrothed to her as a young girl, but that he did not know who she was and she had remained dressed like a man at all times. She had just wanted to be near him again. They insist instead that he knew who she was and that she made him break his priestly vows. She insists her story is true and they begin to flog her. Anna makes them stop and insists she will get the King to release her.She goes to the King but he does not care what happens to Tuptim anymore, since she offended him by running away. She begs him not to take revenge against this girl. She says if he does so, he will prove that all his improvements meant nothing. When he will not relent, she tells him that he is a barbarian. He tells her how would she like it if he made her watch what he does to Tuptim. Anna runs off, fearful of the King for the very first time. A short time later, Tuptim and the young man are burned at the stake together. She dies screaming that he had not sinned and neither had she.Soon after, Anna prepares to leave and says her good-byes to all the children. But the king's wives, whom she also taught, read a letter they wrote begging her to stay. She goes to see Lady Thiang, asking why she had been avoiding her. The Lady points to her wallpaper showing several pictures depicting her own life. First there are two trees representing her and the king, as she was his first wife. Then other pictures show other trees coming between them – his other wives. The king tree grows tall to reach the sky, but loses all its leaves and casts no comforting shadow. Her tree ends up drooping and small; she is unable to help him. Finally a smaller tree grows beside her that she tries in vain to protect from the harsh sun; this represents her son. She says she knows now that her son will become the same as the King, vain and arrogant, rather than a kinder, gentler person as Anna could have taught him to be. Lady Thiang will now remember Anna's failure every time she looks at her son.Shortly afterward, Louis Owens is out riding when his horse stumbles causing the boy to fall and be killed. Anna is devastated. The King sends his consolations to Anna via the Prime Minister, writing that September the 12th will be declared a national day of mourning for her son, and that Anna is to be appointed as Lady Kroo Yai. Chow Koon explains that the letter is an apology not only about her son, but about Tuptim as well. This is the first time he has ever tried to say he is sorry. She tells Chow to please thank the king for her. Prince Chulalongkorn comes to see her and shows her the jackknife Louis gave to him as a parting gift. He offers to return it, but she tells him he can keep it. He says he did not give Louis anything but wishes to give her a gift in his place – a white elephant. He says it is strong and will look after her. She says if he gives her the elephant, who will look after him? "You really need someone to look after you," she says tearfully. They hug, and she realizes she cannot leave him.The King again summons Anna, concerned that she is not taking her medicine. She thanks him for all he has done since her son's death. He asks if she will help him with important correspondence that he has no time to read. She says tearfully that shed like to just stay on with her school. It's the children she wants to help. He agrees.She returns to teach school and stays afterward to answer any questions. One of the King's men comes by saying the King is begging for her help with his correspondence. She goes to see him and sees how frustrated he is, so she agrees to help him as well. Years pass, where consulates are set up for other countries and the Prince becomes a full-grown man with Anna there helping through it all. One day the king's man, now very old himself, summons her very despondently. The Prime Minister tells her that the King is very ill, likely dying. She goes into the library, where he is collapsed on a small bed. He has a letter to read to her, but then tells her in his own words instead. He is glad that she always told him the truth even when he didn't want to hear it. She has helped raised his children to be better men than he was, and he is grateful. He doesn't want to die without telling her of his gratitude, great respect, and confidence in her that grew larger every day. Then he dies peacefully."He tried so hard," she admits, "but he was afraid to ask for help." She wonders what she will do now. The Prime Minister suggests that she should stay and help the Prince. She stays on. The Prince is crowned the new King. His first message is that the ancient national custom of people being on their knees before the King is abolished and that all should stand in front of the king instead as men should do. His subjects all rise up gratefully, as he promises this will be the first of many positive changes to help unite his country. Lady Thiang looks at Anna with gratitude, as does the new King.