Modern organisations are confronted with enormous challenges. The need to continuously adapt to changing environments represents a main challenge for modern organisations. In order to adapt to the requirements of modern environments more easily and more rapidly, organisations become connected into networks. A network organisation is fast becoming a favourite form of the modern organisation. On the basis of an analysis of members in the field of network organisations, this contribution presents the dimensions and definitions of network organisations. In the follow-up, the starting point for a theoretical explanation of network organisations and their different existing forms is presented. The emphasis of the empirical part of the contribution focuses on presenting an analysis of forms of network organisations that are present in Slovenia from the perspective of their shape, development and actual state. Based on an analysis of relevant documentation, it may be concluded that it was the institutional environment which initiated and directed the start-up processes that led to the establishment of contemporary network organisations within Slovenia.