By focussing on several aspects pertaining to the inter-relations between lexis and grammar, I demonstrate in this article that causality in Italian and German is a complex conceptual relationship conveyed by diverse forms of expression that are different from those generally reported in scientific and pedagogical grammars. However, on the basis of certain criteria it is possible to identify several basic types of causal relationships. From a syntactic standpoint, causal relations are divided into ‘cause-effect’ relationships and ‘explicative causes’, while from a semantic standpoint causal relations can be classified as ‘evenemential causes’ and ‘causes of doing’. Within the causes of doing, it is possible to identify two macro-classes of predicates that lead to human actions, specifically the ‘causes external to the agent’ and ‘causes within the agent’. Furthermore, each of these macro-classes, in turn, is made up of different sub-classes of predicates, whose elements comprise different kinds of linguistic means. The proposed taxonomy highlights the wide range of expressive means that characterizes the concept of causality in Italian and German, showing that there are similar semantic classes and categories shared by both languages.