Abstract: Complexity economics has so far had only a small impact on property theory. The impact could be large, and this chapter will set out the conditions for making possible the use of the tools of complex systems theory in the institutional economics of property law. It will show that complex systems theory offers a fresh and counterintuitive account of some familiar aspects of legal and economic property rights. On a theoretical level, many of these features relate to important aspects of complex systems like emergence, feedback, and modularity. Legal, economic, and moral property rights interact, as do the attributes of resources. Even surprisingly misunderstood basics of property law, including its very architecture, can be endogenized and, therefore, understood better. A complexity-based approach to property institutions can bring external and internal perspectives on property into closer alignment.