This article examines teacher professional learning about pedagogy for teachers of students with severe intellectual disabilities within broader teacher education and pedagogical frameworks for this group of learners. The article presents and discusses findings from a USA-England research project, involving classroom observations and interviews with nine teachers of students with severe intellectual disabilities from four specialist public school settings, intended to explore teachers' pedagogical decision-making and learning. The theoretical lens of situated learning and the conceptual lens of evidence-based practice are used to contextualise and examine the teachers' views about the "what," "how" and "when" they learn about pedagogical approaches and strategies. Teachers emphasised the situated and interactional nature of their learning, particularly highlighting the personal responses of students and their relationship with these students. They use this knowledge and understanding to adapt evidence-based strategies and programmes and inform their pedagogical decisions. This affords the concepts of "situated generalization" and "practice based evidence" an influential role in how teachers engage in the process of pedagogical decision-making. An implication for teacher educators is the need to support teachers in making connections of new pedagogical understandings and skills with the individual learning profiles and responses of their students with severe intellectual disabilities.