Alice's Adventures in Wonderland (also known as Alice in Wonderland) is an 1865 English children's novel by Lewis Carroll, a mathematics don at the University of Oxford. It details the story of a girl named Alice who falls through a rabbit hole into a fantasy world of anthropomorphic creatures. It is seen as an example of the literary nonsense genre. The artist John Tenniel provided 42 wood-engraved illustrations for the book.

It received positive reviews upon release and is now one of the best-known works of Victorian literature; its narrative, structure, characters and imagery have had a widespread influence on popular culture and literature, especially in the fantasy genre. It is credited as helping end an era of didacticism in children's literature, inaugurating an era in which writing for children aimed to "delight or entertain". The tale plays with logic, giving the story lasting popularity with adults as well as with children. The titular character Alice shares her name with Alice Liddell, a girl Carroll knew—scholars disagree about the extent to which the character was based upon her.

The book has never been out of print and has been translated into 174 languages. Its legacy includes adaptations to screen, radio, visual art, ballet, opera, and musical theatre, as well as theme parks, board games and video games. Carroll published a sequel in 1871 entitled Through the Looking-Glass and a shortened version for young children, The Nursery "Alice", in 1890.

Alice's Adventures in Wonderland was conceived on 4 July 1862, when Lewis Carroll and the Reverend Robinson Duckworth rowed up the river Isis with the three young daughters of Carroll's friend Henry Liddell: Lorina Charlotte (aged 13; "Prima" in the book's prefatory verse); Alice Pleasance (aged 10; "Secunda" in the verse); and Edith Mary (aged 8; "Tertia" in the verse).

The journey began at Folly Bridge, Oxford, and ended 5 miles (8 km) upstream at Godstow, Oxfordshire. During the trip, Carroll told the girls a story that he described in his diary as "Alice's Adventures Under Ground", which his journal says he "undertook to write out for Alice". Alice Liddell recalled that she asked Carroll to write it down: unlike other stories he had told her, this one she wanted to preserve. She finally received the manuscript more than two years later.

4 July was known as the "golden afternoon", prefaced in the novel as a poem. In fact, the weather around Oxford on 4 July was "cool and rather wet", although at least one scholar has disputed this claim. Scholars debate whether Carroll in fact came up with Alice during the "golden afternoon" or whether the story was developed over a longer period.

Carroll had known the Liddell children since around March 1856, when he befriended Harry Liddell. He had met Lorina by early March as well. In June 1856, he took the children out on the river. Robert Douglas-Fairhurst, who wrote a literary biography of Carroll, suggests that Carroll favoured Alice Pleasance Liddell in particular because her name was ripe for allusion. "Pleasance" means pleasure and the name "Alice" appeared in contemporary works, including the poem "Alice Gray" by William Mee, of which Carroll wrote a parody; Alice is a character in "Dream-Children: A Reverie", a prose piece by Charles Lamb. Carroll, an amateur photographer by the late 1850s, produced many photographic portraits of the Liddell children – and especially of Alice, of which 20 survive.

Carroll began writing the manuscript of the story the next day, although that earliest version is lost. The girls and Carroll took another boat trip a month later, when he elaborated the plot of the story to Alice, and in November, he began working on the manuscript in earnest. To add the finishing touches, he researched natural history in connection with the animals presented in the book and then had the book examined by other children—particularly those of George MacDonald. Though Carroll did add his own illustrations to the original copy, on publication he was advised to find a professional illustrator so that the pictures were more appealing to his audience. He subsequently approached John Tenniel to reinterpret his visions through his own artistic eye, telling him that the story had been well-liked by the children.