A settlor is the person who creates a trust and transfers assets into it. The same role is called a grantor or trustor in the United States; the terms are interchangeable. Once the transfer is complete, the settlor no longer owns the assets. The trustee does, holding them under the terms of the trust deed for the beneficiaries.
That act of giving up ownership is the entire legal engine of a trust. Assets the settlor no longer owns do not pass through the settlor's probate, are not (if things are structured properly and in time) available to the settlor's creditors, and are not automatically subject to the inheritance rules of the settlor's home country.
How much control a settlor can keep without undoing the arrangement is the central tension in trust design. Traditional English law took a hard line: reserve too much and a court may declare the trust a sham. Modern offshore statutes have moved the boundary considerably. The BVI's 2021 amendments let settlors reserve investment powers, the right to replace trustees, and more, without invalidating the trust. The Cook Islands and Nevis go further and let the settlor also be a beneficiary of their own asset protection trust. The trade-off never disappears, though: the more a settlor keeps, the weaker the protection and the more likely a home-country court or tax authority treats the assets as still theirs.
In most offshore planning, one settlor creates the trust, but deeds can have co-settlors, and anyone who later adds assets to a trust is treated as a settlor of that portion, a detail that matters for tax analysis.
Related terms: grantor trust, trust deed, trust protector.