The estate tax in the United States is a tax imposed on the transfer of the "taxable estate" of a deceased person, whether such property is transferred via a will or according to the state laws of intestacy. The estate tax is one part of the Unified Gift and Estate Tax system in the United States. The other part of the system, the gift tax, imposes a tax on transfers of property during a person's life; the gift tax prevents avoidance of the estate tax should a person want to give away his/her estate.

In addition to the federal government, many states also impose an estate tax, with the state version called either an estate tax or an inheritance tax.