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 Washington State, 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 an individual fails to act in the best interest of another party whom they owe a duty to; and negligence, where a party's failure to exercise reasonable care causes harm to another. These claims can be based on Washington State statutes, such as the Revised Code of Washington (RCW), or on principles of common law as interpreted by state and federal courts. It is important for parties to understand the specific legal requirements and elements of each cause of action to effectively pursue or defend against a lawsuit in Washington's civil courts.