Convincing evidence suggests that a considerable number of U.S. students struggle to develop mathematics proficiency. One subgroup of students who have a high probability of mathematical failure is English learners (ELs), who now represent 10% of the U.S. student population; 70% of these students speak Spanish at home (Fry & Passel, 2009). ELs have been the fastest-growing subgroup in U.S. schools over the past 20 years (Francis, Rivera, Lesaux, Kieffer, & Rivera, 2006). In light of this significant influx of ELs and the push for multi-tiered approaches to mathematics instruction, special educators, now more than ever, are working with ELs who are at risk for academic failure but have yet to be identified as needing special education services (Simonsen et al., 2010). Mounting scientific evidence suggests that non-ELs with MD significantly benefit from systematic and explicit instruction (Gersten, 2009). Although the currently available research evidence for ELs with MD is less developed, systematic and explicit mathematics instruction represents a logical starting point for providing effective mathematics instruction to this important subgroup of students.