Although ITK has for long been the subject of academic concern, it is only recently that interest has been shown in the possibility of harnessing it for the purpose of development. This paper reviews a selection of the literature, considers various accounts of the nature of such knowledge and describes some cases, including those—such as botanical knowledge and awareness of changes in eco‐systems—in which ITK often has a comparative advantage. The paper considers alternative modes of interaction between such knowledge and organized science and their feasibility in various situations. Suggestions are made about how research can improve our understanding of ITK and enlarge its practical role in development activities.