In this article, we describe features of learning goals that enable indexing knowledge for teacher education. Learning goals are the key enabler for building a knowledge base for teacher education; they define what counts as essential knowledge for prospective teachers. We argue that 2 characteristics of learning goals support knowledge-building efforts. First, learning goals should be targeted; they must be sufficiently well specified to suggest interventions for supporting learners in achieving them and to indicate the types of evidence needed to determine if the goals have been achieved. Second, learning goals should be shared; they must be mutually understood and committed to by all participants in the knowledge-building process. By drawing on our experience in our local efforts to develop knowledge for preparing prospective elementary mathematics teachers, we illustrate how targeted and shared learning goals support efforts to build a knowledge base for teacher education. We then propose the use of learning progressions for supporting knowledge-building endeavors across sites. (Contains 2 notes.)