Spanish Abstract: En este articulo se discute la ontologia de las instituciones y se critica la idea de que las instituciones estan hechas unicamente de incentivos y acciones individuales. Se sostiene, ademas, que las instituciones no estan constituidas unicamente por acciones de individuos, y que poseen una ontologia propia, reglada y linguistica. Se comparan diversos enfoques sobre el tema y se presentan dos lineas de investigacion sobresalientes en la literatura: el intento de construir una teoria unificada de las instituciones y una propuesta para incluir las reglas constitutivas en la teoria de juegos. English Abstract: This article discusses the ontology of institutions and criticizes the notion that institutions are made only of incentives and individual actions. It is further argued that institutions are not constituted solely on the actions of individuals, and that they have a proper, regulated and linguistic ontology. Several approaches are compared on the subject and two main lines of research are identified in the literature: the attempt to construct a uniied theory of institutions and a proposal to include constitutive rules in game theory.