In U.S. public schools the number of English language learners (ELLs) is increasing, yet U.S. educators are underprepared to teach ELLs in their classrooms. At the secondary level, educators face particular challenges given domain-specific language demands. This mixed-method study examined how professional development (PD) with explicit attention to Culturally Relevant Pedagogy (CRP) and engaging in periodic teacher debrief sessions over the course of several months influenced secondary inservice teachers' perceptions of ELLs' needs and understanding of instructional practices to address the cultural, academic and linguistic needs of ELLs in their classrooms.Quantitative data were gathered via a survey about teachers' perceptions of ELLs (n=10). Qualitative data included two in-depth interviews (n=3), two debriefing sessions (n=3) and an ELL Profile Evaluation task (n=10). Analyses of the participants' responses revealed that teachers had a limited understanding of culturally relevant teaching practices and acknowledged the challenges they face to meet EL learners' particular needs. The most frequently mentioned challenge was the lack of sufficient time for planning and collaborating with colleagues to adapt materials and assessments for ELLs. While participants' reflections demonstrated some learning, the reflection discussions often concentrated on why particular instructional strategies were useful for ELLs regarding their language (mostly vocabulary) needs rather than relating to the students' cultural backgrounds and experiences. As a result, teachers did not implement some of the practices that are key to meeting the goals of culturally relevant teaching. Implications of the results, recommendations for future research, limitations of the study, and concluding remarks are included. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]