Pan-Indianism is a philosophical and political approach promoting unity and, to some extent, cultural homogenization among different Indigenous groups in the Americas regardless of tribal distinctions and cultural differences.

This approach to political organizing is primarily associated with Native Americans organizing for social justice and cultural revitalization in the Continental United States but has spread to some other Indigenous communities as well, especially in Canada. Inuit and Métis people may consider themselves part of the broader pan-Aboriginal community or some variation thereof. Some academics have also used the term pan-Amerindianism to distinguish from other peoples known as "Indians." Some pan-Indian organizations seek to pool the resources of Native groups to protect the interests of indigenous peoples across the world.

Tecumseh's Confederacy is considered to be an early example of Pan-Indianism. As a confederation founded on the premise of indigenous unity against American expansionism, it united many of the tribes of the Great Lakes region. At the meeting between Tecumseh and then governor of the Indiana Territory, William Henry Harrison at Vincennes, Tecumseh called for collective ownership of land, arguing that the land belonged to everyone.

In 1912, members of the Creek, Choctaw, Cherokee, and Chickasaw tribes, united by their opposition to Allotment, formed the Four Mothers Society for collective political action. Also, in 1912, the Alaskan Native Brotherhood and Sisterhood came together, centering on their shared interest in protecting Native resources. In 1934, Congress passed the Indian Reorganization Act, which reversed assimilation and allotment policies. This act granted "legal sanction to tribal landholdings; returned unsold allotted lands to tribes; made provisions for the purchase of new lands; encouraged tribal constitutions, systems of justice, and business corporations; expanded educational opportunities through new facilities and loans ...; advocated the hiring of Indians by the Office of Indian Affairs ...; extended the Indian Trust Status; and granted Indians Religious Freedom."

Before there were successful national and continental organizations, there were several regional bodies that united multiple nations (tribes or bands) within the context of post-settlement politics. The Grand General Indian Council of Ontario was organized with missionary assistance in the 1870s and persisted until 1938. Likewise, the Allied Tribes of British Columbia were created in 1916.

In 1911, the first national Indian political organization in the US was created, the Society of American Indians. This organization pursued such things as better Indian educational programs and improved living conditions. This was paralleled by the establishment of the League of Indians of Canada in 1919, Canada's first Aboriginal organization that was national in scope.

The Society of American Indians was the most influential of the early pan-Indian organizations. It played a critical role in advocating Indian citizenship, which was finally granted by the Indian Citizenship Act of 1924.

Before World War II and throughout the 1940s and '50s, Native activism was less developed and for the most part non-violent. Many leaders made a genuine effort to work with the American government. In 1923, as a symbolic gesture, Deskaheh, a Cayuga chief, traveled to the League of Nations in Geneva in hopes of obtaining recognition of his tribe's sovereignty, but his request was denied. In 1939, the Tonawanda Band of the Seneca tribe issued a "Declaration of Independence" to the state of New York. It was ignored, and natives who broke state law were arrested. In other cases, American Indian tribes struggled to maintain their sovereignty over tribal land that had been granted to them by treaties with the federal government. Unrelated Native American groups, and Americans in general, began to notice and sympathize with their aims.^{[citation needed]}