Shadow IT coexists with mandated information systems. Developed and applied by nonIT domain experts, it is as a rule, but not exclusively, used for resolving nonroutine issues, for which mandated IS does not have appropriate functions. Shadow IT solutions are not supported or controlled by IT departments. The aim of the paper is to show to which extent shadow IT has been researched, as this area has not yet received the necessary attention from both academia and business. A systematic literature review was conducted in order to find the papers covering the topic of shadow IT. The following electronic databases were searched: Web of Science (Thomson Reuters), Scopus (Elsevier), and AIS Electronic Library (The Association for Information Systems (AIS)). More than half of the analysed papers are case studies in one or more organizations. The papers were published mostly in scientific conferences and in scientific journals. Based on the literature review, the reasons for shadow IT occurrence, the possibility of its management, as well as its advantages and disadvantages are presented. The most important conclusions and views regarding shadow IT, according to the authors’ opinion, are indicated at the end. The limitation of a systematic literature review is that only papers published in English are analysed. Besides identifying papers covering the shadow IT topics, the reasons for the emergence of shadow IT, the possibilities of its management and its advantages and disadvantages are systematized.