The No Child Left Behind education act mandates that school districts develop supplemental educational service programs for students not demonstrating mathematical proficiency on state standardized math assessments. Yet there is limited understanding of issues related to supplemental educational service math programs. The purpose of this qualitative study was to investigate a local after school math program to offer insight on the low math achievement for economically disadvantaged students involved in the program. Constructivist theories of math reform and education for economically disadvantaged students and English language learners guided this study of 10 teachers and 15 of their students in a diverse urban elementary school in the northeastern United States. Two questions guided this research: One on the mathematical achievement of economically disadvantaged students in the local after school math program; the other on the nature of professional development for teachers of supplemental educational service programs. Data from observations and teacher interviews were analyzed using constructivist grounded theory coding procedures. Data revealed themes centered on program structures, student attributes, instructional strategies, professional collaboration, curriculum, and professional development. Findings further revealed educational communities can increase student math achievement through strategic teacher training. The final project addresses social change with the creation of a research supported action plan for teacher professional development within the local supplemental educational math program. This research is significant to school leaders in the advancement of supplemental educational service math programs for academically diverse learners.