The question of how best to teach learners who are deaf or hard of hearing (DHH) is perhaps the oldest topic in any area of education for children with diverse learning needs. Developments in a number of fields have accounted for more DHH learners achieving educational outcomes commensurate with their hearing-age peers than at any point in that long history. Efforts to further develop and implement effective educational practices with these learners continue, with an abundance of interventions proposed in the literature and in practice. Despite this, evidence for their efficacy remains limited. Such evidence as there is tends to be drawn from observations of professional practice and not always from the outcomes of high-quality research. This is not to say that a lack of research evidence for a particular educational practice means that it is necessarily ineffective or should not be used. Rather, it is to acknowledge the preeminence of quality research outcomes as the cornerstone of an evidence-base for educational practice with DHH learners while recognizing that contributions can come from two other sources: the expertise and experiences of professionals involved in the education of DHH learners in educational settings, and the views and preferences of DHH learners and their families about how the best educational outcomes can be achieved. The vast majority of DHH learners are educated in regular classrooms alongside their hearing peers, including a significant minority whose primary or preferred language is a signed language. Questions of how best to facilitate access to regular classrooms for those DHH learners are inextricably linked to issues in three areas: (a) communication, language, and literacy; (b) classroom access; and (c) pedagogical practices and other educational supports. The first area covers the unique set of challenges that relate to DHH learners acquiring a language (i.e., whether that be spoken or signed) and how best to support their ongoing development and use of their communication, language, and literacy skills in the classroom. The other two sets of issues, relate to the difficulties that are typically encountered by DHH learners in gaining access to the regular classroom curriculum through their preferred language and mode of communication (i.e., how best to access the auditory and visual environment of the classroom on an equitable basis with their hearing peers), and how best to support that access through instructional techniques and/or specialist support services. In all three areas there remains the challenge of assembling an evidence base for practice from quality research evidence.