Many of the social challenges we care about feel like messy, wicked knots (or a pile of tangled headphones). When we pull on a thread in one place, we create new, tighter knots elsewhere. The messy nature of these challenges is due to, among other things, their complexity. Understanding key features of complex problems helps us understand why problems in education can be especially resistant to change. The purpose of this brief is to share (some) characteristics of complex problems, and introduce system dynamics as a set of tools for managing this complexity.