ITG FAQ #14 Answer-Do tribal governments have the authority to impose their own tax system?
The power to levy taxes is an aspect of retained sovereignty of Indian tribes, except where it has been limited or withdrawn by federal authority. Many tribes have taxing authorities. The example used here is the Navajo Tribe. They have an Office of the Navajo Tax Commission, a Mission Statement, a Code, regulations, auditors, audit plans, and auditing standards.