This action research study evaluated and sought to improve teacher professional development (PD) strategies designed to instill culturally and linguistically responsive pedagogies in classrooms at an elementary school. The study assessed participants' practical application and perceptions of the applicability of English learner instruction strategies and culturally responsive pedagogy in mainstream classrooms. The first phase of the study included piloting the survey instrument with participants who attended a conference on bilingual education, and conducting a thorough literature review. The action research study was then designed so that 29 teachers in a public elementary school received professional development (PD). Nine of the teachers that participated in the PD met the sampling criteria and were willing to participate in the study--four in the first iteration and five in the second. Observations, pre- and post-PD surveys, and participant interviews provided insight into the teachers' PD needs, the impact of the intervention, and provided feedback on the opportunities and challenges throughout the teachers' learning experience. Teacher-participants were observed prior to their participation in the PD intervention using a protocol with observable components of sheltered instruction and culturally responsive teaching. A two sample t-test for means determined that three observable elements were statistically significant on the post-intervention observations: language objectives clearly defined, displayed, and reviewed with students; concepts explicitly linked to students' background experiences; and instruction is scaffolded to promote culturally and linguistically diverse (CLD) student learning. In the first iteration, 15 themes emerged from the interviews during which the four participants discussed the content received in the PD and how they would apply it in their classrooms. Second iteration interviews further supported that participants felt the professional development and strategies were applicable to their practice. Surveys administered before and after each iteration supported that the PD helped participants become more comfortable with teaching culturally and linguistically diverse students after receiving professional development (PD) on the topic. The researcher was also a participant and facilitator relying on deep reflection to improve the PD modules. The results from iterations one and two were carefully analyzed to complete the third iteration--a practical guide to planning professional development for creating culturally and linguistically responsive classrooms. Although strategies should be adapted to meet the needs of each school's population, academic offerings, and themes (as in the case of magnet schools), the professional development guide resulting from this research can help administrators and faculty collect baseline data, plan and deliver PD, prioritize and implement strategies, and collect post-PD data to determine if the PD has impacted instruction. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]