In this paper, we discuss the problematic use of the term dyslexia. Noting that there are no unambiguous objective diagnostic criteria for 'dyslexia', in part because this term is understood in multiple ways, we discuss its relevance for informing educational assessment, intervention and resourcing. We conclude by highlighting how current approaches to dyslexia diagnosis and remediation typically fail to serve the needs of large numbers of struggling readers. In their place, we advocate 'Response to Intervention' as an ethically and educationally justified approach to tackling severe reading difficulties, but also highlight continuing challenges to its effective implementation.