Vine Victor Deloria Jr. (March 26, 1933 – November 13, 2005) was an author, theologian, historian, and activist for Native American rights. He is widely known for his book Custer Died for Your Sins: An Indian Manifesto (1969), which helped attract national attention to Native American issues in the same year as the Alcatraz-Red Power Movement. From 1964 to 1967, he served as executive director of the National Congress of American Indians, increasing its membership of tribes from 19 to 156. Beginning in 1977, he was a board member of the National Museum of the American Indian, which now has buildings in both New York City and in Washington, DC, on the Mall.

Deloria began his academic career in 1970 at Western Washington State College at Bellingham, Washington. He became Professor of Political Science at the University of Arizona (1978–1990), where he established the first master's degree program in American Indian Studies in the United States. In 1990, Deloria began teaching at the University of Colorado Boulder. In 2000, he returned to Arizona and taught at the College of Law. NBC News called Vine Deloria the "star of the American Indian renaissance."

Deloria's writing and advocacy focused on contemporary American Indian movements and the treaty rights of Native American tribes. His later writings, particularly Red Earth, White Lies, rejected prevailing scientific accounts of Western Hemisphere prehistory that he thought contradicted Native American traditional history. For instance, he rejected the existence of Bering land bridge and embraced human–dinosaur coexistence. Deloria's critics wrote that his literalist views contributed to pseudoscience. He also falsely claimed the English introduced scalping to North America which is refuted by many archaeological examples of pre-contact scalping.

Vine Deloria Jr. was born in 1933, in Martin, South Dakota, near the Oglala Lakota Pine Ridge Indian Reservation. He was the son of Barbara Sloat (née Eastburn) and Vine Victor Deloria Sr. (1901–1990). His surname is derived from the name of a French trapper, Philippe des Lauriers, who settled and married into a Yankton community of the Dakota people in the early 19th century. His father studied English and Christian theology at St. Stephen's College and became an Episcopal archdeacon and missionary on the Standing Rock Indian Reservation. His father transferred his and his children's tribal membership from the Yankton Sioux to Standing Rock. Vine Sr.'s sister Ella Deloria (1881–1971) was an anthropologist. Vine Jr.'s paternal grandfather was Tipi Sapa (Black Lodge), also known as the Rev. Philip Joseph Deloria, an Episcopal priest and a leader of the Yankton band of the Dakota Nation. His paternal grandmother was Mary Sully, daughter of Alfred Sully, a general in the American Civil War and Indian Wars, and his French-Yankton wife; and granddaughter of painter Thomas Sully.

Deloria was first educated at reservation schools, then graduated from Kent School in 1951. He graduated from Iowa State University in 1958 with a degree in general science. Deloria served in the United States Marines from 1954 through 1956.

Originally planning to be a minister like his father, Deloria in 1963 earned a theology degree from the Augustana Theological Seminary in Rock Island, Illinois. In the late 1960s, he returned to graduate study and earned a J.D. degree from University of Colorado Law School in 1970.

In 1964, Deloria was elected executive director of the National Congress of American Indians. During his three-year term, the organization went from bankruptcy to solvency, and membership increased from 19 to 156 tribes. Through the years, he was involved with many Native American organizations.

Deloria was the founder and head of the Institute of American Indian Law and the Institute for the Development of Indian law. Both the Institute for the Development of Indian Law and the Institute of American Indian Law sought to develop and provide legal training and assistance to Native American tribes, organizations, and courts. In 1971, they sought to form a national taxation defense strategy to fight federal, state, and municipal governments' attempts to impose taxes on various aspects of tribal and individual economic life. In 1972 the Institute published Taxing Those They Found Here: An Examination of the Tax Exempt Status of the American Indian by Jay Vincent White, with Deloria contributing the Foreword.