IMS Learning Design (IMS LD 2003) is an open specification that can be used to specify a wide range of pedagogical strategies as formal models. Such formal models then can be interpreted and executed by IMS LD compatible players to support online learning. This chapter introduces the basic knowledge required to effectively use IMS LD. First of all, we present fundamental principles behind IMS LD. Then, we briefly introduce IMS LD implementation and application process. Finally, how to model learning designs using IMS LD is explained through demonstrating the whole procedure to model a use case.