Causes of action in civil litigation are specific claims provided by law that serve as the basis for parties to a lawsuit to recover money or property from each other—or to provide other legal or equitable relief, such as a court order requiring or prohibiting some act (injunctive relief). Examples of causes of action include breach of contract, fraud, breach of fiduciary duty, and negligence. Causes of action (also called claims) are usually located in a state or federal statute, or in court opinions (common law).

In Missouri, causes of action in civil litigation are the legal grounds on which a plaintiff bases their lawsuit to seek remedies such as monetary compensation, restitution, or injunctive relief. Common causes of action include breach of contract, where one party fails to fulfill the terms of a contract; fraud, involving intentional deception to secure unfair or unlawful gain; breach of fiduciary duty, where a party with a duty to act in another's best interest fails to do so; and negligence, where a party's failure to exercise reasonable care causes harm. These claims can be based on Missouri state statutes, federal laws, or developed through court decisions (common law). For instance, the Missouri Revised Statutes contain specific provisions for various types of civil actions, and the decisions of Missouri courts contribute to the state's common law. An attorney can help identify the appropriate cause of action based on the facts of a case and the applicable law.