Custer Died for Your Sins: An Indian Manifesto is a 1969 non-fiction book by the lawyer, professor and writer Vine Deloria, Jr.

Custer Died for Your Sins was significant in its presentation of Native Americans as a people who were able to retain their tribal society and morality, while existing in the modern world.

The book advocates Native American religion, and encourages church groups to lay aside their theological differences and help the tribes whose members they sought to convert.

[1] Deloria noted that humor was a critical aspect of social control in tribal relationships, as an alternate means of pointing out flaws and errors without a direct confrontation that would affect the dignity of the accused.

Deloria uses this chapter as a response to those individuals who believe that Native Americans have no place in modern society as they are, with tribalism as the central point of contention.

Deloria argues that tribalism is so inherent to the Native identity that it will one day lead them to do things once thought impossible by “Indian and non-Indian alike”.

Due to its importance in the Red Power movement, an original copy of the book was displayed in the National Museum of the American Indian's long-term exhibit "Our Lives: Contemporary Life and Identities".