Generally, no. Only parties with legal standing (i.e., those with a direct financial interest in a trust) have the right to sue a trustee. However, as the Malcolm-Jamal Warner trust dispute demonstrates, there are important exceptions to this rule.
Although the late actor’s widow, Tenisha Warner, was not named as a beneficiary of his trust, she is pursuing claims against the trustee, his mother Pamela Warner, as a creditor. When creditors are owed a valid debt, they may have standing to take legal action against a trustee and seek repayment from trust assets in certain circumstances.
Non-beneficiaries may also have standing to sue when they were unintentionally omitted or wrongfully excluded from an estate plan due to undue influence, fraud, or other misconduct. In those cases, they may seek to recover an inheritance or restore their rights as a beneficiary.