In this article, the concept of action competence is presented and an attempt is made to locate it within the concept of general educational theory. The concept of action competence, it is argued, should occupy a central position in the theory of environmental education as many of the crucial educational problems concerning a political liberal education are united in this concept. The preoccupation with action competence as an educational concept is based on scepticism about the educational paradigm in environmental education which manifests itself partly in a marked tendency to individualisation and partly in a tendency to regard the educational task as a question of behaviour modification. At the same time, action competence should be seen as a necessary alternative to the traditional, science-oriented approach to environmental education. Examples from developmental work in Danish schools are used to clarify and demarcate the concept of "action" from "activity" and "behaviour change". Different kinds of actions are discussed, environmental actions are identified and a distinction is drawn between "direct" and "indirect" environmental actions. Finally, four problem areas are identified which require future research. (Contains 1 figure.) [This article was reprinted from "Environmental Education Research" (1997) 3(2), pp. 163-178 (see EJ546571).]