This chapter illustrates how to optimize the return on investment (ROI) of enterprise architecture. Enterprise architecture is a blueprint for defining the structure and operation of organizations such as local, state, and federal agencies. Done well, enterprise architecture results in leaner and more effective information systems that satisfy organizational goals and objectives. This chapter introduces a suite of simple metrics and models for measuring the ROI of enterprise architecture. This chapter also introduces real options, which is a contemporary approach to measuring ROI. Whereas typical measures tend to underestimate ROI, real options have the ability to unearth business value hidden deep within the economics of investments in enterprise architecture.