The purpose of this study was to: (1) describe elementary teachers' perceptions on their preparedness to implement the English Language Arts Common Core State Standards (ELA-CCSS); (2) determine how perceptions influenced changes in instructional practices; and (3) to explore ELA-CCSS implementation challenges and/or barriers in supporting teacher development. This study was conducted using a multi-methods research design involving quantitative data from a survey, and qualitative data from interviews. The conceptual framework for this study centered around a history of the Common Core State Standards, education reform implementation research, understandings about the Common Core State Standards, and reconstructing teacher practice. Results revealed that professional development effect on instructional practice was limited; preparedness was a learning process; a mismatch existed between preparedness and instructional practices in relation to teacher change; and supports offered in district were not strong enough to advance reform implementation. Districts, administrators, and teachers are encouraged to integrate teacher participation in decision-making processes; develop a robust professional learning community model; ensure alignment of teacher supports with actual teachers' needs, and augment teacher agency as a barrier to implementation passivity. v DEDICATION There are many significant people in my life that I would like to dedicate this dissertation, who have served as the greatest inspiration allowing me to accomplish a doctorate degree. My loving parents, I proudly dedicate this dissertation with immeasurable gratitude. Without your enviable support of me, your generous love, inexplicable patience and acceptance, blind confidence in me, and unceasing encouragement-I'm not sure I would have accomplished this. Por estas cosas y mucho más, les doy mil gracias. Este doctorado es tanto suyo como mío. Mamá, tengo la alegría de poder mirar lo orgullosa que estas de mí. Papá, siento tu alegría desde el cielo, donde estás al lado de Dios. Vedant and Claritamy two beautiful children, who served as the greatest inspiration for pursuing one more educational goal. Since coming into my life, you've been the motivation behind so much of what I've done. I know I was not always there for you (mentally or even physically) as much as I would have liked to during this journey, but this sacrifice was done in the service of safeguarding your future. Alma, Sylvia, Chava, and Lupitaqueridos hermanos-I also dedicate this dissertation to you. Thank you for believing in me, for your unconditional support and encouragement along the way-including your forever mantra of "tu puedes hacerlo." vi Johnny, Aaron, Arath, and Betzaidamy beloved nephews and niece, whom I always wanted to set a good example for you as your aunt, while opening doors for you to attain your own educational goals. My husband Eddie, for his love, support and encouragement including the numerous times you had to listen to my "dissertation issues," which were not alwa...