This chapter explores how systemic functional linguistics (SFL) can contribute to secondary teachers' effectiveness for teaching disciplinary literacies to refugee youth in the United States. The chapter describes the Milltown Multimodal/Multiliteracies (MMM) Collaborative, an SFL-based professional development partnership between a large public university and a high poverty urban school serving high proportions of refugee youth with limited or interrupted formal education from Guatemala, Iraq, Mexico, Rwanda, and Vietnam. We present data from longitudinal case studies of these students' school and work experiences as they participated in MMM curricular interventions, including SFL analyses of changes in the ways they produced and interpreted different genres of texts. These data illustrate how the MMM Collaborative constructed contact zones that supported the expansion of refugee students' semiotic resources and semiotic mobility. Within these contact zones, refugee students drew on gestures, graphics, images, their home and peer languages, and English in learning to read and write disciplinary genres. Further, through their participation in genre pedagogy, refugee students expanded their use of a range of semiotic resources, including the ability to read and write disciplinary texts in English. However, students' social, academic, and economic mobility appeared to be strongly influenced by their immigration status. These findings offer a nuanced perspective on what it means to be a refugee youth tasked with learning disciplinary literacies in the U.S. public school system today, and signal productive ways to rethink the role of critical applied linguistics in teacher education practices. [For the complete volume, "Refugee Education across the Lifespan: Mapping Experiences of Language Learning and Use. Educational Linguistics. Volume 50," see ED660722.]