Intelligent Tutoring Systems (ITS) are computer learning environments that offer personalized instruction to help learners master knowledge and skills. ITSs are superior to typical computer-based training because their intelligent algorithms can adapt to the needs of the individual learner at a fine-grained level. However, most ITSs do not take advantage of the inherent benefit of incorporating multiple representations of the knowledge they teach. This chapter discusses how multiple representations can be integrated into a single system using knowledge components, and how this is incorporated into an expanded student model. As an example, we describe ElectronixTutor, which integrates five ITSs as well as a number of other learning resources to teach electronics.