A tax is a charge or levy of money made by a governmental entity (state, local, or federal) against a taxpayer—usually a U.S. citizen or a person living or working in the United States. There are many kinds of taxes, including income tax, capital-gains tax, property tax, franchise tax, gift tax, ad valorem tax, sales tax, use tax, inheritance tax, and estate tax.

In Maine, as in other states, residents and businesses are subject to various types of taxes levied by state and local governments, as well as the federal government. Income tax is collected at both the state and federal levels, with Maine having a progressive state income tax system with rates that vary depending on the taxpayer's income bracket. Capital gains are also taxed, and they are generally treated as income for tax purposes. Property taxes are primarily administered at the local level, with municipalities assessing taxes on real estate and personal property. Maine does not have a franchise tax. The state imposes a sales tax on the purchase of most goods and services, and a complementary use tax on goods purchased out-of-state for use in Maine. While there is no gift tax in Maine, the state does levy an estate tax on the transfer of an individual's assets after death, with certain exemptions and rates depending on the value of the estate. It's important to note that federal taxes, including federal income tax, capital gains tax, and federal estate and gift taxes, are also applicable to Maine residents according to federal law.