Investigating teachers’ cognitions, both in general education and in language teaching, has gained momentum in the past few decades. Yet, the practical knowledge-base (PKB) of practitioners who teach languages to students with special needs has not been amply explored. The present study aimed to investigate the personal PKB of EFL teachers of individuals with Down syndrome (IDS). To this end, several classes of three Iranian EFL special education teachers were observed and video-recorded, and the teachers were interviewed using the stimulated-recall method. Analysing the data resulted in the emergence and conceptualization of a framework characterizing the PKB of Iranian EFL special-education teachers in terms of eight major knowledge types: knowledge of learners’ characteristics, learner-based pedagogical knowledge, knowledge of classroom management, visual-impact knowledge, knowledge of self, curriculum knowledge, language subject knowledge, and contextual knowledge. These knowledge types and particularly their subcomponents are argued to be heavily reminiscent of the teachers’ learner-centered (vs. content-oriented) attention to their students’ special needs, characteristics, motivations, limitations, potentials, and deprivations. Dealing with an under-researched domain, the study is hoped to sensitize ELT special-education teachers, teacher trainers, and policy-makers to the possibilities and requirements of quality teaching to IDS.