Rationality as a central concept in occidental philosophy and social sciences never seemed to spark the interest of Ludwig Wittgenstein. Here it will be argued that – although “rationality” does not explicitly show up in his works – Wittgenstein not only deals with questions definitively ascribed to the conceptual history of the term, but he also works towards a transformation of the concept. Wittgenstein’s efforts were aimed at showing that there is nothing within human nature that defines what is perceived as rational, irrational, or non-rational, but that the differences are produced in human language and action. The necessity of such a transformative perspective on rationality, however, can only be adequately captured by recognizing the taxonomy of some of Wittgenstein’s best-known concepts. It will be argued that this systematic arrangement has to be completed by another concept: the context.