The objective of problem solving in technology and engineering is to change the material world for the benefit of society, through processes of design. Design thinking – or design-based thinking – is thus a unique and crucial component of problem solving in technology and engineering. It also has connections to arts and design studies in which creativity and innovative thinking are central. In addition, design-based thinking has been applied in many other areas, disciplines, and educational initiatives such as designs for learning and design-based pedagogy. In this chapter, we shall expound on the notion of design-based thinking, in relation to problem solving in technology and engineering and more broadly across the STEM disciplines. We argue that the three components authentic thinking, visual thinking, and entrepreneurial thinking constitute essential conceptual elements of design-based thinking. We relate this conception of design-based thinking to problem solving, teaching interventions, and curriculum design in 21st-century STEM education.