Lakota religion or Lakota spirituality is the traditional Native American religion of the Lakota people. It is practiced primarily in the North American Great Plains, within Lakota communities on reservations in North Dakota and South Dakota. The tradition has no formal leadership or organizational structure and displays much internal variation.

Central to Lakota religion is the concept of wakʽą, an energy or power permeating the universe. The unified totality of wakʽą is termed Wakʽą Tʽąką and is regarded as the source of all things. Lakota religionists believe that, due to their shared possession of wakʽą, humans exist in a state of kinship with all life forms, a relationship that informs adherents' behavior. The Lakota worldview includes various supernatural wakʽą beings, the wakʽąpi, who may be benevolent or malevolent towards humanity. Prayers are given to the wakʽąpi to secure their assistance, often facilitated through the smoking of a sacred pipe or the provision of offerings, usually cotton flags or tobacco. Various rituals are important to Lakota life, seven of them presented as having been given by a benevolent wakʽą spirit, White Buffalo Calf Woman. These include the sweat lodge purification ceremony, the vision quest, and the sun dance. A ritual specialist, usually called a wičháša wakhá ("holy man"), is responsible for healing and other tasks. The most common of these specialists is the yuwípi wičháša (yuwípi man), whose yuwípi ritual typically invokes spirits for healing.

One of the three main populations speaking a Sioux language, the Lakota had emerged as a distinct nation composed of seven groups by the 19th century. Many of their religious traditions reflected commonalities with those of other Sioux nations as well as non-Sioux communities like the Cheyenne. In the 1860s and 1870s, the United States government relocated most of the Lakota to the Great Sioux Reservation, where concerted efforts were made to convert them to Christianity. Most Lakota ultimately converted, although many also continued to practice certain Lakota traditions. The U.S. government also implemented measures to suppress traditional rites, for instance banning the sun dance in 1883, although traditional perspectives were documented in the 19th and early 20th centuries by practitioners like Black Elk. Encouraged by the American Indian Movement, the 1960s and 1970s saw revitalization efforts to revive Lakota traditional religion. In the late 20th century, Lakota practices increasingly influenced other Native American religions across North America.

Many Lakota practice their traditional religion alongside Christianity, typically Catholicism, Episcopalianism, or the peyote religion of the Native American Church. For these individuals, Wakʽą Tʽąką is often identified with the Christian God. Lakota traditions have also been adopted by many non-Native Americans, especially New Agers, a tendency condemned by some Lakota spokespeople as cultural appropriation.

Their name deriving from a term meaning "allies", the Lakota comprise the seven westernmost groups of the Sioux peoples. Other terms for the Lakota include the Western Sioux, Teton Sioux, Tetons, Teton Dakotas, or the Thíthuwa (Prairie Dwellers). The Lakota had formed into seven subdivisions by the 19th century. The two southern groups are the Oglálas and the Sičháŋǧu, while the five northern groups are the Itázipčho, Húŋkpapȟa, Mnikȟówožu, Sihásapa, and Oóhenuŋpa, sometimes collectively termed the Saône.

Lakota religion has been described as an indigenous religion, and as a primal religion. There is no centralized authority in control of the religion, which is non-dogmatic, with no specific creeds. The tradition is transmitted orally, being open to individual interpretation, and displaying internal variation in its practice. Some practitioners have an attitude of religious pluralism and thus involve themselves in other religious traditions. This usually means types of Christianity, especially Catholicism or Episcopalianism, or sometimes the peyotism of the Native American Church. Other Lakota identify themselves strictly with just one religion, with this particularly the case for Christian fundamentalists. They may perceive some conflict between the two; some Lakota will remove any Christian imagery from a room if a traditional ceremony is to be performed there.

Native American religions have always adapted in response to environmental changes and interactions with other communities, including after encountering Christianity. This adaptation is evident in Lakota religion, with change being observed since textual records of it were first made during the 18th century. Much of this adaptation is the result of visions experienced by its practitioners, but also reflects influences absorbed, directly or indirectly, from neighboring Plains peoples as well as those from the Eastern Woodlands, Subarctic, and Great Basin. At the same time, tradition is a vital concept for Lakota communities, one that is regularly invoked to legitimate a link between contemporary practices and those of the past.

Among the Lakota, there are difficulties in drawing boundaries between religion and other areas of culture; as is the case with many Native American religious traditions, Lakota religion permeates all areas of life. In the Lakota language, there is no term cognate to the English word "religion", although Christian missionaries active among the Lakota have tried to devise one. Some Lakota prefer to refer to their religious traditions as a "way of life", while elsewhere some writers have referred to it as "Lakota spirituality." The latter reflects the fact that many Lakota, like certain other Native Americans, prefer to describe their traditional beliefs and practices as "spirituality", largely as a reaction against the Christian missionary use of the term "religion". The anthropologist David C. Posthumus suggested that the terms "religion" and "spirituality" could be used interchangeably when discussing Lakota traditions.