Trusts are legal entities, similar to individual people and corporations. Therefore, you may be able to sue a trust for certain reasons — just as you would a company or a person. However, you would probably want to examine the specific rules for California before determining whether your intended legal action would have a chance of achieving your goals.
As explained on FindLaw, there is a concept called fiduciary duty that binds certain professionals to their respective ethical codes. Examples might include lawyers, financial advisors and, most relevant to this discussion, people who administrate trusts. One of the reasons you may want to take action against a trust is if you have evidence that a person or group of people involved in its administration acted appropriately. In these cases, you may have an option in addition to or in place of suing the trust directly — bringing suit against the responsible parties.
These actions are similar to those you might take if you believed that an executor of a will acted inappropriately. However, even though wills and trusts are both common estate planning tools, will and trust litigation are not the same. It is important to base any action you take on an understanding of the legal concepts and possible consequences involved with the specific material situation in question.
Furthermore, whether you decide to take action against a trust directly or pursue a case against a trustee, you would want to make sure that your actions had a chance of completing your specific goals. These types of procedures all have different timelines and may receive different levels of opposition from the various other parties involved. Therefore, please do not use this article as legal advice. It is only intended as general background information.