When the objective of managing socio-technical systems includes enhancing their long-term resilience and sustainability, the problem inhibits the characteristics of a complex adaptive system. In such cases, the decision makers (DMs) and modelers are both internal and integral parts of the system. Such systems involve many stakeholders who affect the decisions, and many others who will be affected by them. In such circumstances, a single objective function cannot be representative of everyone’s perspective. Also, lack of applicable data further complicates decision making. In this chapter we introduce multi-criteria decision making (MCDM) techniques and tools that can aid in the decision-making process shaping the behavior of socio-technical systems. We provide an introduction to the MCDM science and methods of application, discuss two open-source MCDM online tools, and present and solve a problem in the area of building design by using the methods introduced in this chapter.