Learning disabilities (LDs) have long been presumed to be a neurological disorder resulting from a deficit in 1 or more cognitive processes. Although the emphasis on cognitive processing disorders has been included in the definition since the term was coined, and although it arguably represents the key distinguishing characteristic of LDs, it also has been the least well-operationalized component of the LD construct. In this article, first a brief synthesis of the emerging research examining the connection between cognitive processing deficits and academic achievement is presented. Next, the difficulty of operationalizing the implications from this body of research is described, as is the importance of developing an LD identification model that accurately reflects current understandings of the construct. Combined models for identification that rely on the use of both a student's response to intervention and a comprehensive evaluation of cognitive processes are presented as best practice. Finally, implications for transitioning school-based LD identification models are discussed.