An excise, or excise tax, is any duty on a category of goods that is normally levied by a government at the moment of manufacture for domestic consumption. This makes excise different from a sales tax or value-added tax (which are levied at a point of sale) or from customs duties (which are levied on goods when they cross a designated border).

An excise is considered an indirect tax, meaning that the producer or seller who pays the levy to the government is expected to try to recover their loss by raising the price paid by the eventual buyer of the goods. Excise is thus a tax that relates to a quantity, not a value, as opposed to the value-added tax which concerns the value of a good or service. Excises are typically imposed in addition to an indirect tax such as a sales tax or value-added tax (VAT). Typically, an excise is distinguished from a sales tax or VAT in three ways:

Typical examples of excise duties are taxes on alcohol and alcoholic beverages ; alcohol tax, for example, may consist of a levy of n euros per hectolitre of alcohol sold ; manufactured tobacco (cigars, cigarettes, etc.), energy products (oil, gas, etc.), vehicles or so-called "luxury" products. The legislator's aim is to discourage the consumption of products it considers to have a negative externality (sometimes referred to as sin tax).

More recently, excise duty has been introduced on certain forms of transport considered to be polluting (such as air transport) or on the consumption of products that generate polluting waste that is little or not at all recycled or harmful to the environment (such as electronic products, certain plastic packaging, etc.).

These are the oldest sources of revenue for governments around the world. In 2020, consumption taxes accounted for 30% of total tax revenues in OECD countries on average, equivalent to 9.9% of GDP in these countries.

Excise has existed in English since the late 15th century and was borrowed from Middle Dutch echijns and excijs, meaning 'excise on wine or beer', which was apparently altered from earlier (13th century) assise, assijs, which meant simply a tax on consumption and is related to Medieval Latin accisia, assisia, assisa 'tax, excise duty'. The exact derivation is unclear and is presumed to come from several roots.

Excise was introduced to England from the Netherlands in the mid-17th century under the Puritan regime, as a tax, an excise duty, levied on drinks in 1650. In the British Isles, upon the Restoration of the Monarchy, many of the Puritan social restrictions were overturned, but excise was re-introduced, under the Tenures Abolition Act 1660, in lieu of rent, for tenancies of royally-owned land which had not already become socage. Although the affected tenancies were limited in number, the excise was levied more generally; at the time, there was thought to be a rough correspondence between the wealthy manufacturers of affected goods, and the wealthy tenants of royal land.

Excise duties or taxes continued to serve political as well as financial ends. Public safety and health, public morals, environmental protection, and national defense are all rationales for the imposition of an excise. In defense of excises on strong drink, Adam Smith wrote: "It has for some time past been the policy of Great Britain to discourage the consumption of spirituous liquors, on account of their supposed tendency to ruin the health and to corrupt the morals of the common people." Samuel Johnson was less flattering in his 1755 dictionary: