Background/Context A number of recent policies have specifically attacked immigrants and English Language Learners (ELLs), including Georgia's HB 87 (2011), Arizona's SB 1070 (2010), and Alabama's HB 56 (2011), among others. The policy focus of this study is Arizona's HB 2064 (2006), which added additional requirements that mandate tracking students by English language proficiency and separating English language instruction from subject matter for ELL students. Few scholars have considered how these broad social policies impact professional development (PD)-induced classroom change, especially in mathematics education. This sociopolitical context cannot help but affect teachers’ willingness to take on new practices in PD and thus affect educational opportunities for Latinos and English Language Learners. Yet, policies that target ELLs have not received much attention within mathematics education or PD. This exploratory study details teacher change produced by mathematics PD efforts before and after a new ELD policy was implemented in order to better understand this intersection. Purpose/Objective/Research Question/Focus of Study The teachers in this study participated in mathematics professional development focusing on Cognitively Guided Instruction (CGI). This exploratory research documents how teachers experimented in their classrooms before and after this policy was implemented and teachers’ views of HB 2064. Two research questions guided the study: 1) How did the mathematics PD affect change in teacher knowledge and classroom practice? and 2) How did the conflicting policy and PD efforts influence change in elementary mathematics instruction? Setting This research took place in the Monroe Elementary School District, an urban school district in Arizona. Three schools participated in mathematics professional development based on CGI principles. The student population was 95% Hispanic and 46% ELLs, and 89% of students received free or reduced lunch. Therefore, Arizona's policies had the potential to greatly impact the student population in this school. Population/Participants/Subjects The professional development was implemented with three groups of K–3 teachers (n=44). Across the PD, just over one fourth of participating teachers were bilingual in Spanish and English. Intervention/Program/Practice The professional development focused on the principles of CGI, combining earlier work on student strategies and problem types (Carpenter, Fennema, Franke, Levi, & Empson, 1999) with more recent work on algebraic thinking (Carpenter, Franke, & Levi, 2003) and counting (Schwerdtfeger & Chan, 2007). This model of professional development focuses teachers on the development of student thinking, problem types for various mathematical operations, and building instruction from this knowledge base. The PD consisted of monthly on-site workgroup meetings and weekly on-site visits to support teachers in their classrooms. Research Design The research team conducted a mixed methods study of teacher change across the district. The study followed teachers for two years—one year before the policy was implemented and the year it was implemented—documenting the practices teachers maintained in their elementary mathematics classrooms. The study used a mixed methods design to respond to the two research questions (Creswell, 2003). A teacher knowledge assessment was used to see if teachers were gaining new knowledge as they implemented the principles of the PD. Observations allowed for the study to look at teacher experimentation in classrooms. Finally, an interview on the policy and its impact on their classroom practices was performed to add more understanding to why teachers did or did not implement more PD practices. Findings/Results Teacher knowledge change was minimal across the professional development. However, the data on change in practice suggest that more practices were adopted before the policy was implemented than during implementation. In contrast, teachers reported that the policy had minimal effect on their mathematics instruction. This conflict, between change in practice and the perceived lack of policy impact, seemed to be due to teachers’ view of mathematics and language as fundamentally separate. It also was related to an alignment between teacher beliefs and the views embedded in the policy. Conclusions/Recommendations The findings raise concerns about the conflict between PD and policy in generating teacher change. New questions emerge from this work about taking into consideration the sociopolitical context when researching PD efforts focused on intersections between policy and subject matter. Questions also emerge about the alignment of ideology in policy with teachers’ beliefs. The authors call for work in mathematics PD that takes on the intersections between policies and PD efforts and that targets particular student populations. Additionally, more research would be beneficial for understanding the impact of the sociopolitical context on teacher change efforts.