This embedded mixed method study addresses the problems teachers have reported in believing themselves capable to implement the Common Core State Standards with students in special education. This study examines the effect professional development on implementing the Common Core State Standards had on the participating teachers’ self-efficacy beliefs. The participants (N=21) in this study were drawn from a 20-day professional development for teachers based on implementing the Common Core State Standards. The instrument used in the study was the Teacher Efficacy Beliefs System-Self. Data were subject to both statistical and qualitative analysis. The results of this study provide insight into the self-efficacy beliefs of the participants during and shortly after professional development about implementing the Common Core State Standards with students in special education. The Wilcoxon test of signed ranks revealed a significant increase in the TEB-S subscale areas of Accommodating Individual Differences and Managing Learning Routines, but not in Positive Classroom Climate. Qualitative analysis of data found both support for the statistical findings and also contradicted the statistical findings. Further qualitative analysis showed that practices presented in the professional development such as using the arts, formative assessment, and technology were effective in maintaining their teachers’ self-efficacy beliefs after professional development. Factors unrelated to the professional development, such as support from administrators and colleagues and poorly working technology were not supportive in carrying over the increase in teachers’ self-efficacy beliefs in implementing the Common Core State Standards with students in special education. The study is framed by Social Cognitive Theory and organized into 5 parts. Chapter I provides an overview of the study. Chapter II includes a review of literature related to teachers’ self-efficacy belief’s Common Core State Standards, and professional development. Chapter III describes the methodology of the study. Chapter IV presents the results of the analysis of data. Chapter IV reports the findings of the study and presents the conclusions of the study and ideas for future research.