Tintin in Tibet (French: Tintin au Tibet) is the twentieth volume of The Adventures of Tintin, the comics series by Belgian cartoonist Hergé. It was serialised weekly from September 1958 to November 1959 in Tintin magazine and published as a book in 1960. Hergé considered it his favourite Tintin adventure and an emotional effort, as he created it while suffering from traumatic nightmares and a personal conflict while deciding to leave his wife of three decades for a younger woman. The story tells of the young reporter Tintin in search of his friend Chang Chong-Chen, who the authorities claim has died in a plane crash in the Himalayas. Convinced that Chang has survived and accompanied only by Snowy, Captain Haddock and the Sherpa guide Tharkey, Tintin crosses the Himalayas to the plateau of Tibet, along the way encountering the mysterious Yeti.

Following The Red Sea Sharks (1958) and its large number of characters, Tintin in Tibet differs from other stories in the series in that it features only a few familiar characters and is also Hergé's only adventure not to pit Tintin against an antagonist. Themes in Hergé's story include extrasensory perception, the mysticism of Tibetan Buddhism, and friendship. Translated into 32 languages, Tintin in Tibet was widely acclaimed by critics and is generally considered to be Hergé's finest work; it has also been praised by the Dalai Lama, who awarded it the Light of Truth Award. The story was a commercial success and was published in book form by Casterman shortly after its conclusion; the series itself became a defining part of the Franco-Belgian comics tradition. Tintin in Tibet was adapted for the 1991 Ellipse/Nelvana animated series The Adventures of Tintin, the 1992–93 BBC Radio 5 dramatisation of the Adventures, the 1996 video game of the same name, and the 2005–06 Young Vic musical Hergé's Adventures of Tintin; it was also prominently featured in the 2003 documentary Tintin and I and has been the subject of a museum exhibition.

While on holiday at a resort in the French Alps with Snowy and Captain Haddock, Tintin reads about a plane crash in the Gosain Than Massif in the Himalayas of Tibet. He then has a vision of his friend Chang Chong-Chen, badly injured and calling for help from the wreckage of the crashed plane. Convinced of Chang's survival, Tintin flies to Kathmandu, via Delhi, with Snowy and a skeptical Captain Haddock. They hire a Sherpa named Tharkey and, accompanied by porters, travel overland from Nepal towards the crash site.

The porters abandon the group in fear when mysterious tracks are found, while Tintin, Haddock and Tharkey go on and eventually reach the crash site. Tintin sets off with Snowy to trace Chang's steps, and finds a cave where Chang has carved his name on a rock. On leaving the cave, he encounters a snowstorm and glimpses what seems to be a human silhouette. Tharkey believes that Tintin saw the Yeti and convinces him to abandon his friend and return with him to Nepal, since the area is too large to search. Tintin spots a scarf on a cliff face, concludes Chang is nearby, and continues with only the Captain. While attempting to scale a cliff face, Haddock slips and hangs out of reach, imperilling Tintin, who is tied to him. He tells Tintin to cut the rope to save himself, but Tintin refuses. Haddock tries to cut it himself, but drops his knife, alerting Tharkey, who has returned in time to rescue them. They try to camp for the night but lose their tent and must trek onwards, unable to sleep lest they freeze, arriving within sight of the Buddhist monastery of Khor-Biyong before being caught in an avalanche.

Blessed Lightning, a monk at the monastery, has a vision of Tintin, Snowy, Haddock, and Tharkey in danger. Tintin regains consciousness and, too weak to walk, gives Snowy a note to deliver. Snowy runs to the monastery, loses the message, but is recognised as the dog from Blessed Lightning's vision. Tintin, Haddock and Tharkey regain consciousness in the monastery and are brought before the Grand Abbot. The Abbot tells Tintin to abandon his quest, but Blessed Lightning has another vision, through which Tintin learns that Chang is still alive inside a mountain cave at the Horn of the Yak—and that the Yeti is also there. Tintin and Haddock travel on to the Horn of the Yak.

They arrive at a cave. Tintin ventures inside and finds Chang, who is feverish and shaking. The Yeti suddenly appears, revealed as a large anthropoid, reacting with anger at Tintin's attempt to take Chang. As it lunges at Tintin, the flash bulb of Tintin's camera goes off, and scares the Yeti away. Chang tells Tintin that the Yeti saved his life after the crash. Upon returning to inhabited lands, the friends are surprised to be met by the Grand Abbot, who presents Tintin with a khata scarf in honour of the bravery he has shown for his friend Chang. As the party travels home, Chang muses that the Yeti is not a wild animal, but has a human soul. The Yeti sadly watches their departure from a distance.

In October 1957, Hergé sent his publisher, Casterman, the cover of his completed nineteenth Tintin adventure, The Red Sea Sharks, and for several weeks considered plot ideas for his next story. Fondly recalling the Scouting days of his youth, his first idea was to send Tintin back to the United States, as in the third adventure, Tintin in America, to help a group of Native Americans defend their land from a large corporation that wished to drill for oil; on reflection, Hergé came to believe that retracing old ground would be a step backwards. Another idea had Tintin striving to prove that Haddock's butler Nestor was framed for a crime committed by his old employers, the Bird brothers. He dismissed this as well, but kept the idea of an adventure with no guns or violence—the only Tintin story without an antagonist. A third idea sent Tintin and Professor Calculus to a snow-covered polar region, where a stranded group of explorers need Calculus to save them from food poisoning. He abandoned this plot also, but kept the setting in a snowy environment and decided to focus, not on Calculus, but on his main character Tintin.

A collaborator of Hergé's, Jacques Van Melkebeke, had suggested in 1954 to set a story in Tibet, likely influenced by the play he adapted for Hergé in the 1940s, M. Boullock a disparu (Mr. Boullock's Disappearance). Bernard Heuvelmans, a cryptozoologist who had helped Hergé envision lunar exploration for the two-part Destination Moon and Explorers on the Moon, had given him a copy of his book Sur la piste des bêtes ignorées (On the Trail of Unknown Animals) in 1955, inscribing on the inside the suggestion that one day Tintin should meet the Yeti. By 1958, Hergé decided that Tibet would be the setting of Tintin's next Adventure. Initial ideas for the title were Le museau de la vache (The Cow's Snout), Le museau de l'ours (The Bear's Snout), and Le museau du yak (The Yak's Snout), all of which refer to the mountain in the latter part of the story. Although it was initially claimed that "market research" chose the title Tintin in Tibet suggesting sales would be better if the book used Tintin's name in the title, entertainment producer and author Harry Thompson suggested "the title reflected the solo nature of [Tintin's] undertaking".