Veganism is the practice of abstaining from the use of animal products and the consumption of animal source foods, and an associated philosophy that rejects the commodity status of animals. A person who practices veganism is known as a vegan; the word is also used to describe foods and materials that are compatible with veganism.

Ethical veganism excludes all forms of animal use, whether in agriculture for labour or food (e.g., meat, fish and other animal seafood, eggs, honey, and dairy products such as milk or cheese), in clothing and industry (e.g., leather, wool, fur, and some cosmetics), in entertainment (e.g., zoos, exotic pets, and circuses), or in services (e.g., mounted police, working animals, and animal testing). People who follow a vegan diet for the benefits to the environment, their health or for religion are regularly also described as vegans, especially by non-vegans.

Although, individuals have been renouncing the consumption of products of animal origin since ancient times, the term "veganism" itself was only coined in 1944 by Donald and Dorothy Watson. The aim was to differentiate it from vegetarianism, which rejects the consumption of meat but accepts the consumption of other products of animal origin, such as milk, dairy products, eggs, and other "uses involving exploitation". Interest in veganism increased significantly in the 2010s.

Vegetarianism can be traced back to the Indus Valley civilization in 3300–1300 BCE in the Indian subcontinent, particularly in northern and western ancient India. Early vegetarians included Indian philosophers such as Parshavnatha, Mahavira, Acharya Kundakunda, Umaswati, Samantabhadra, and Valluvar, as well as the Indian emperors Chandragupta Maurya and Ashoka. The earliest recorded vegans, who predated the term "vegan" but were explicitly vegan as opposed to vegetarian, include al-Ma'arri (who predated the word vegan by a millennium) and Lewis Gompertz.

One of the earliest known vegans was the Arab poet al-Ma'arri, famous for his poem "I No Longer Steal From Nature". (c. 973 – c. 1057). Their arguments were based on health, the transmigration of souls, animal welfare, and the view—espoused by Porphyry in De Abstinentia ab Esu Animalium ("On Abstinence from Animal Food", c. 268 – c. 270)—that if humans deserve justice, then so do animals.

Vegetarianism established itself as a significant movement in 19th-century Britain and the United States. A minority of vegetarians avoided animal food entirely. In 1813, the poet Percy Bysshe Shelley published A Vindication of Natural Diet, advocating "abstinence from animal food and spirituous liquors", and in 1815, William Lambe, a London physician, said that his "water and vegetable diet" could cure anything from tuberculosis to acne. Lambe called animal food a "habitual irritation" and argued that "milk eating and flesh-eating are but branches of a common system and they must stand or fall together". Sylvester Graham's meatless Graham diet—mostly fruit, vegetables, water, and bread made at home with stoneground flour—became popular as a health remedy in the 1830s in the United States. The first known vegan cookbook was Asenath Nicholson's Kitchen Philosophy for Vegetarians, published in 1849.

Several vegan communities were established around this time. In Massachusetts, Amos Bronson Alcott, father of the novelist Louisa May Alcott, opened the Temple School in 1834 and Fruitlands in 1844, and in England, James Pierrepont Greaves founded the Concordium, a vegan community at Alcott House on Ham Common, in 1838.

C. W. Daniel published an early vegan cookbook, Rupert H. Wheldon's No Animal Food: Two Essays and 100 Recipes, in 1910. The consumption of milk and eggs became a battleground over the following decades within the Vegetarian Society. There were regular discussions about it in the Vegetarian Messenger; it appears from the correspondence pages that many opponents of veganism were vegetarians.