A trust fund is a collection of assets such as funds (cash, stocks, CDs, etc.) and/or real estate that is administered by a trustee in the interest of a beneficiary. A trust fund is governed by a set of rules collectively called the "trust deed". This can specify when the trust fund beneficiary may begin drawing an income from the trust. In the case of minor children, the trustee is generally authorized to make distributions as necessary on their behalf. This practice may also continue into adulthood if the beneficiary has a mental disability that makes him/her incompetent in the eyes of the law.

Large trust funds are usually handled by banks or trust institutions that specialize in this type of account. A trust fund can be established for a number of different purposes. Some are designed to limit taxation. Others can be used to bypass probate when the grantor (the person who put the assets in the trust) dies. Anyone with assets can set up a trust fund. They are especially useful for people whose estate is worth enough to make it subject to state or federal estate taxes.