Much has been said and written about indigenous knowledge systems (IKS) or, as it is also termed, traditional ecological knowledge. My paper does not intend to discuss how it should be termed, although this is also an important issue as the way we name it frames the possibilities we open for this kind of knowledge. The paper rather looks historically at indigenous knowledge inclusion in school curricula, taking as an example the practice in Mozambique. So far, many strategies in so-called culturally inclusive science curricula tend to take students along the pathway of cultural assimilation by integrating IKS into World Modern Science topics. IKS is therefore taken as an instrument for serving the goals of World Modern Science. I argue that we need to find legitimated theories to integrate IKS in order to counteract the practice of teaching IKS in science classrooms detached from its own sociocultural context.