This chapter is a succinct stop for orientation to the concept of complex situations, as the latter are an inherent part of working in health systems. Knowing whether you are in a simple or a complex problem territory and adjusting your approach accordingly is important for decision-makers. The important thing is to be able to recognize these situations. Drawing from the classic literature on the topic, the main features of simple, complicated, and complex situations are described. It is acknowledged that commissioners in health services are often dealing with, or contributing to dealing with complex situations. Addressing this complexity will need to draw on the different perspectives, skills, and experiences that may come from many disciplines and there are often no quick solutions as such. Some practical tips are offered.