There has been a major shift in the demographic landscape in US public schools within the last decade. The population of English learners (ELs) has increased rapidly. How to increase opportunities for them to learn is the focal point of discussion in many urban and rural schools. With this change in the cultural and linguistic landscape, content-area teachers are challenged to meet the needs of ELs due to the lack of resources in teacher professional development. Among the numerous studies of pedagogical strategies about teaching ELs, few have focused on fostering ELs' development of speaking. In this article, we review literature through the theoretical lens of willingness to communicate (WTC). Framed by a discussion of the individual, linguistic, and contextual factors which influence WTC, five principles of promoting ELs' WTC are suggested. We argue that the understanding of factors influencing ELs' WTC and strategies to promote their WTC serve as crucial components of the knowledge, skills, and dispositions which effective teachers of ELs must have.