An action axiom is an axiom that embodies a criterion for recommending action. Action axioms are of the form "IF a given condition holds, THEN the following should be done." Decision theory and, hence, decision analysis are based on the maximum expected utility (MEU) action axiom. In general, the principle for action embodied by an action axiom (such as MEU) is highly defensible and its scope is very broad.

See also: Decision Tree, Norm, Normative and Prescriptive.