Various tax systems grant a tax exemption to certain organizations, persons, income, property or other items taxable under the system. Such status may provide a potential taxpayer complete relief from tax, tax at a reduced rate, or tax on only a portion of the items subject to tax. Examples include exemption of charitable organizations from property taxes and income taxes, exemptions provided to veterans, and exemptions under cross-border or multi-jurisdictional principles. Tax exemption generally refers to a statutory exception to a general rule rather than the mere absence of taxation in particular circumstances (i.e., an exclusion). Tax exemption also generally refers to removal from taxation of a particular item or class rather than a reduction of taxable items by way of deduction of other items (i.e., a deduction). Tax exemptions may theoretically be granted at any governmental level that imposes taxation, though in some broader systems restraints are imposed on such exemptions by lower tier governmental units.

Specific monetary exemptions

Some jurisdictions allow for a specific monetary reduction of the tax base, which may be referred to as an exemption. For example, the U.S. Federal and many state tax systems allow a deduction of a specified dollar amount for each of several categories of "personal exemptions." Similar amounts may be called "personal allowances." Some systems may provide thresholds at which such exemptions or allowances are phased out or removed.

Exempt organizations

Some governments grant broad exclusions from all taxation for certain types of organization. As an example, the UK generally exempts public charities from rates, VAT, income tax, and certain other taxes. The exclusions may be restricted to entities having various characteristics. The exclusions may be inherent in definitions or restrictions outside the tax law itself.