Abstract: Action-based legal theory is a discrete branch of praxeology and the basis of an emerging school of jurisprudence related to, but distinct from, natural law. Legal theory and economic theory share content that is part of praxeology itself: the action axiom, the a priori of argumentation, universalizable property theory, and counterfactual-deductive methodology. Praxeological property-norm justification is separate from the strictly ethical “ought” question of selecting ends in an action context. Examples of action-based jurisprudence are found in existing “Austro-libertarian” literature. Legal theory and legal practice must remain distinct and work closely together if justice is to be found in real cases. Legal theorizing was shaped in religious ethical contexts, which contributed to confused field boundaries between law and ethics. The carrot and stick influence of rulers on theorists has distorted conventional economics and jurisprudence in particular directions over the course of centuries. An action-based approach is relatively immune to such sources of distortion in its methods and conclusions, but has tended historically to be marginalized from conventional institutions for this same reason.