Anyone who is 18 or older, or legally recognized as an adult, and mentally fit can be involved in a small claims case. If a person is underage or not mentally competent, they need someone appointed by the court, known as a guardian ad litem, to represent them in the case.

This law states that you can't take a claim to small claims court if you were assigned the claim by someone else. However, there are exceptions: a bankruptcy trustee can deal with claims as part of their job, and holders of specific financial agreements (like security agreements) can file claims if they are not doing so just to collect debts for others. Also, local governments that handle their own workers' compensation can file claims for reimbursement.

If you run a business under a made-up name and want to file a claim related to that business in small claims court, you need to prove you've followed rules about registering and advertising that name. If you haven't sorted out those requirements, your case will be thrown out, but you can refile it once you have. The meanings of terms like 'fictitious business name' are set out in other specific laws.