Dreamsnake is a 1978 science fiction novel by American writer Vonda N. McIntyre. It is an expansion of her 1973 novelette "Of Mist, and Grass, and Sand", for which she won her first Nebula Award in 1974. The story is set on Earth after a nuclear holocaust. The central character, Snake, is a healer who uses genetically modified serpents to cure sickness—one snake is an alien "dreamsnake", whose venom gives dying people pleasant dreams. The novel follows Snake as she seeks to replace her dreamsnake after its death.

The book is considered an example of second-wave feminism in science fiction. McIntyre subverted conventionally gendered narratives by rewriting a typical heroic quest to place a woman at its center, and by using devices such as avoiding gender pronouns to challenge expectations about characters' gender identities. Dreamsnake also explored varying social structures and sexual paradigms from a feminist perspective, and examined themes of healing and cross-cultural interaction.

The novel was well-received, winning the Nebula Award, the Hugo Award, and the Locus Poll Award in 1979. The strength and self-sufficiency of Snake as a protagonist were noted by several commentators. Reviewers also praised McIntyre's writing and the book's themes. Scholar Diane Wood wrote that Dreamsnake demonstrated "science fiction's potential to produce aesthetic pleasure through experimentation with linguistic and cultural codes", and author Ursula K. Le Guin called it "a book like a mountain stream—fast, clean, clear, exciting, beautiful".

In 1971, Vonda N. McIntyre, then living in Seattle, set up the Clarion West writers' workshop, which she helped run through 1973. One of the workshop's instructors was Ursula K. Le Guin. During a 1972 workshop session, one of the assignments was to create a story from two randomly chosen words, one pastoral, and one related to technology. McIntyre's effort would become her 1973 short story "Of Mist, and Grass, and Sand". That story grew into Dreamsnake, and was used unchanged as the first chapter of the novel, which also incorporated two other pieces by McIntyre: "The Broken Dome" and "The Serpent's Death", both published in 1978. Dreamsnake, McIntyre's second novel, was released by Houghton Mifflin in 1978, with a cover illustration by Stephen Alexander.

The story is set after a nuclear holocaust that "destroyed everyone who knew or cared about the reasons it had happened". Most animal species are extinct, regions of the planet are radioactive, and the sky is hidden by dust. Human society is depicted as existing in what journalist Sam Jordison describes as "low-tech tribalism": the character Arevin, for instance, has never seen a book. The exception is the single city of Center, which has sophisticated technology and is in contact with other planets, but which has a rigidly hierarchical structure and does not permit outsiders to enter. The city also serves as the setting for McIntyre's first novel, The Exile Waiting (1975). The protagonist of Dreamsnake is Snake, a healer who uses snake venom in her trade. She travels with three genetically engineered snakes; a rattlesnake, named Sand, a cobra, named Mist, and a "dreamsnake" named Grass, from an alien world, and who relieves the pain of dying patients by letting them dream.

The healer Snake comes to a nomadic tribe's camp to treat a boy, Stavin, who has a tumor. While her cobra Mist manufactures an antidote in her venom glands, she leaves Grass, her dreamsnake, with Stavin to help him sleep. One of the nomads, Arevin, helps Snake control Mist as the cobra undergoes convulsions through the night, despite his people's terror of snakes. She returns to Stavin in the morning to find that his parents have mortally wounded Grass, afraid he would hurt the boy. Despite her anger, she allows Mist to bite Stavin and inject medication to heal the tumor. The leader of the nomads apologizes to Snake, and Arevin asks her to stay with them, but Snake explains that she needs a dreamsnake for her work and must return home and ask for a new one. She expresses fear that the other healers will take her snakes and cast her out instead. As she leaves, Arevin asks her to return someday.

Snake stops at an oasis, where she is asked to help Jesse, a woman badly injured in a fall from her horse. Jesse's partner Merideth takes Snake to their camp, leaving Snake's baggage at the oasis. Snake finds that Jesse has broken her spine, leaving her paralyzed, something Snake cannot heal. Merideth and their third partner Alex convince Jesse that they should return to Center, where Jesse is from, in the hope that the off-worlders there may be able to help her. Wandering around near the camp, Snake sees the body of Jesse's horse and realizes that they fell into a radioactive crater remaining after a nuclear war, where Jesse lay long enough to contract fatal radiation poisoning. Snake offers to let Mist bite Jesse and relieve her pain; Jesse accepts, and Merideth and Alex bid her farewell. Before she dies of a brain hemorrhage prior to Mist's bite, Jesse tells Snake that her family is indebted to Snake and could help her obtain another dreamsnake.

Returning to the oasis, Snake finds that someone has rifled through her belongings and stolen her maps and journal. Grum, a caravan leader also camped there, says it was the work of a "crazy". Back among the nomads, Arevin decides to go after Snake. Snake crosses the western desert to the town of Mountainside, where the mayor's son Gabriel asks her to heal the mayor. While staying with them, Snake invites Gabriel to sleep with her. After he expresses hesitation, she learns that he impregnated a friend as a result of being improperly taught "biocontrol", the birth control method practiced by humans post-apocalypse, and that this led to a difficult relationship with his father. She tells him he can still learn, and suggests he find a different teacher and learn effective methods when he leaves Mountainside, as he intends to do.