This study investigated whether collaboration between science teachers and ELD teachers would result in changes to teachers' perceptions about their role and responsibility to support English Learners in their science classes and whether professional learning opportunities provided would result in planned implementation of strategies and practices to support those students. Science teachers of English Learners benefitted from professional learning opportunities that engage science teachers and English Language Development teachers in the process of working together to help revise lesson plans to better support English Learners. This Professional Learning intervention engaged science and ELD teachers in 10 sessions conducted over the course of 5 weeks. Using a qualitative research design, data from pre and post interviews, observations from professional learning sessions, reflections from learning sessions and teacher created activities and lesson plans revealed that science teachers benefit from learning about California's expectations for teaching English Learners, the typologies, proficiency levels and capabilities of students at different proficiency levels and opportunities to practice implementing strategies and practices that support English Learners in their Science classes with coaching from ELD teachers. [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.]