When entrepreneurship educators today refer to “Lean Startup,” they are often describing a real-world, customer-centric approach to early concept development and innovation that 1) begins with a search for product–market fit, 2) progresses through cycles of hypothesis testing across the various building blocks of a potential business model, and 3) reaches a provisional “end of the beginning” with a launched startup poised for rapid growth. Since the phrase was first introduced, in 2008, Lean Startup has secured global embrace – as evidenced by best-selling books on the topic, university courses and programs built around its core concepts, and a multi-year, multimillion-dollar initiative funded by the United States’ National Science Foundation. Lean Startup clearly describes an approach that is philosophically and practically aligned with much of what entrepreneurs do and entrepreneurship educators teach. That said, little is truly known about Lean Startup’s unique or differentiated ability to deliver positive business results. Further, little academic attention has been given to how Lean Startup aligns with or adds to the larger set of tools, methods, perspectives and theories, long-lived and new, that populate a truly comprehensive portfolio in entrepreneurship education. This chapter reviews the emergence of the Lean Startup approach – deconstructing its component parts in an effort to begin asking the questions that might form the basis of more robust research around Lean Startup methods and outcomes.