What amendment excluded native Americans from citizenship?

The Indian Citizenship Act of 1924 granted U.S. citizenship to Native Americans, but prior to that, they were largely excluded from citizenship under the Constitution. The 14th Amendment, ratified in 1868, defined citizenship but did not explicitly extend it to Native Americans, as they were considered members of sovereign tribes rather than U.S. citizens. Consequently, many Native Americans remained without citizenship rights until the 20th century, despite some states granting them citizenship earlier.