避税港（英语：tax haven）指的是税率很低、甚至是完全免征税款的国家或地区，但可能只有个别税种较低，适用于特定分类的个人或商业机构。

个人要受益于避税港的其中一个方法，就是迁徙到该地区，使法律上只需缴交税项给免税港政府。另外，个人或商业机构也可以在避税港，成立附属机构或独立的法律实体（即公司或普通法法制里的基金），资产移动到新公司后便可在套现获利，从而缴交较低或者免除税款。不过，利用这种方法到底算是避税还是逃税，难以一概而论。这视乎相关国家或地区、还有相关的个人或机构的个别情况。

避税港一般是小型岛国或缺乏天然资源的地区。一般认为成立避税港能有效吸引外国资本，从而发展本土基建和经济。由于外国一般难以追查、取缔成立于避税港里面的活动，犯罪份子有可能把其犯罪资金大量引入避税港，这通称为「洗黑钱」。

A tax haven is a jurisdiction where particular taxes, such as an inheritance tax or income tax, are levied at a low rate or not at all. It may also refer to a state, country, or territory which maintains a system of financial secrecy, which enables foreign individuals to hide assets or income to avoid or reduce taxes in the home jurisdiction. Earnings from income generated from real estate (i.e. by renting property owned in an offshore jurisdiction) can also be eliminated in this way. If taxes (if any) are paid in the tax haven jurisdiction, companies can avoid taxes in their home jurisdiction because the tax had already been paid in the lower tax rate jurisdiction. Some taxes (such as inheritance tax on the real estate, VAT on the initial purchase price of the real estate, or transfer tax, annual immovable property taxes, and municipal real estate taxes) cannot be avoided or reduced, as these are levied by the country the real estate where the property is located, and hence need to be paid just the same as any other resident of that country. The only thing that can be done is picking a country that has the smallest rates on these taxes (or even no such taxes at all) before buying any real estate.