Due to technological advances, IT is increasingly introduced and managed outside of (or even hidden from) an organisation’s IT department. As a result, researchers and practitioners have created multiple concepts describing different facets and trends of this development. While the individual concepts typically focus on different aspects, there are overlaps between these concepts. This effect hampers research progress as it creates redundancies and separate streams of knowledge development. We propose a taxonomy of the concepts Lightweight IT, IT Consumerisation, Bring Your Own Device, Shadow IT, and Business-Managed IT to solve this research problem based on a systematic literature review. For this purpose, we derive characterising dimensions of each concept from existing studies and analyse literature according to the usage of terms. As a result, we can describe and delineate the concepts. Thus, we contribute a taxonomy of IT outside the IT department to improve the transfer of research results between research streams.