This lesson presents some of the most consolidated management concepts of tourism firms and destinations, both conceived as systems, shedding light on their mutual functionality. Special attention is devoted to the key conditions - i.e., conditions of systemness (Cafferata, 2016) that need to be verified by tourism firms and destina5ons to become and remain competitive systems. On this conceptual base, we explain the concepts of governance and management of the aforesaid systems, highlighting their protagonists, key decisions, and operations. In addition, some useful management tools – for tourism firms and destinations that aim to become and remain competitive systems over time – are briefly presented. Through this lesson, the reader can acquire specific knowledge about the opportunity offered by ‘‘systems thinking” to understand the nature of both tourism firms and destinations, their general administration, and the basic conditions of their competitiveness and evolution.