This article reports on a project implemented to help middle school teachers provide evidence-based instruction and intervention to students with mathematics learning disabilities (MLD) and mathematics difficulties (MD). Multiple sources--interviews, surveys, and field notes from formal and informal observations--were used to gather data on teacher perceptions and feedback on what worked and what did not in this professional development effort. We also examined the mathematics achievement of students with MLD and MD and compared their growth to that of their typically performing peers at the two participating schools. We highlight and discuss the key issues and concerns that emerged from this implementation study.