An irrevocable trust is a trust that cannot be amended, modified, or terminated by the grantor, settlor, or trustor (person who created the trust) after it is created—at least not without the permission of the beneficiary or beneficiaries.

Irrevocable trusts generally offer tax benefits that revocable trusts do not. This is primarily because the grantor, settlor, or trustor who creates an irrevocable trust permanently transfers (gifts) all right of ownership of the assets to the trust and its beneficiaries.

Laws vary from state to state but a trust is usually irrevocable unless the grantor, settlor, or trustor specifies otherwise in the trust agreement.

In Massachusetts, an irrevocable trust is a legal arrangement where the grantor (the person who creates the trust) transfers their assets into the trust and relinquishes all rights to amend, modify, or terminate the trust. Once the assets are placed into an irrevocable trust, they are no longer considered the property of the grantor, but rather of the trust itself and its beneficiaries. This transfer can provide certain tax advantages, as the assets may no longer be part of the grantor's taxable estate. Massachusetts law, like the law in many states, presumes that a trust is revocable unless the trust instrument explicitly states it is irrevocable. The terms of the trust are governed by the trust document and Massachusetts state statutes, which include provisions under the Massachusetts Uniform Trust Code. It is important to note that under certain circumstances, with the consent of the beneficiaries or by court order, modifications to an irrevocable trust may be possible even in Massachusetts.