Using restricted-use data from the 2011 National Assessment of Educational Progress mathematics assessment, the current study examined the relationship between the presence of elementary mathematics coaches and specialists (MCSs) and the mathematics achievement of more than 190,000 fourth-grade students in more than 7,400 schools nationwide. In addition, the study explored how that relationship differed for students with and without identified disabilities, a vital concern with the continued focus of equity in mathematics education. Hierarchical linear modeling, with adjustments for composite covariates and controls as well as sampling weights, was used to examine each research question. Results showed promise for the use of full-time elementary MCSs to support students' overall and specific content-area mathematics achievement. This positive relationship did not hold true for the use of part-time MCSs, nor was a differential effect found based on students' disability status.