In this work we present RAT-OWL, a Prot ́eg ́e 4.3 Plugin for reasoning about typicality in preferential Description Logics. RAT-OWL allows the user to reason in a nonmonotonic extension of Description Logics based on the notion of “rational closure”. This logic extends standard Description Logics in order to express “typical” properties, that can be directly specified by means of a typicality operator T: T(C) v D represents that “typical Cs are also Ds”. We show experimental results, indicating that the performances of RAT-OWL are promising.