This implementation project focused on supporting teachers who provide mathematics instruction and/or intervention to students with mathematics learning disabilities (MLD) and mathematics difficulties (MD). The research team worked with three schools, over three years. Instructional delivery differed across schools, primarily in setting and amount of time students received mathematics instruction. Given these various contexts, the project provided job-embedded professional development to support each school's implementation of the three key features of the project: using evidence-based curricula, using evidence-based practices, and responsive coaching. By focusing middle school intervention on algebraic reasoning--which requires a strong understanding of rational numbers, variables, and equivalence--students with MLD and MD made gains across the school year that were comparable to their peers. However, the gains were not enough to close the achievement gap between students with MLD and MD and students who are on grade-level. Given the three-year implementation of this project included two years of altered instruction due to COVID-19 restrictions, it is encouraging that students with MLD and MD made gains that were comparable to their peers. The project worked with eight teachers across the three schools and found variability among their implementation and how they preferred to work with the research team. From an implementation science perspective, one year of implementing a new innovation is likely insufficient to fully build capacity in teachers to sustain the practices learned from the JEPD. However, teachers indicated that they learned many new things related to teaching students with MLD and MD through the JEPD, which is encouraging.