Literature in this field of English language learners (ELLs) in US public schools indicates that the needs of these adolescent ELLs are not being met due to a lack of language support and inaccessibility to content. This research examined the enactment of a curriculum with preservice teachers designed to address the specific needs of adolescent ELLs in content area classrooms and the implementation of components of the SIOP (Sheltered Instruction Observation Protocol) Model into their lesson planning and delivery. This study was conducted in an urban university in the Midwest within a single class for junior-level undergraduate content area preservice teacher candidates of adolescents. There were 31 voluntary participants who were preservice content-area teachers: art, n=2; English language arts, n=5; math, n=12; music, n=4; science, n=4; social studies, n=4. Coursework assignments were collected as data sources. Additional data collected included instructor notes/reflections on weekly class sessions. The research questions addressed the changes the preservice teachers showed in their knowledge of and capacity to explain and apply second language acquisition processes, a scaffolding model for ELLs called SIOP, and disciplinary-specific aspects of literacy in their content areas. Data analysis showed that there was evidence of improvement in their knowledge, ability to explain and apply, and integrate disciplinary literacy within the SIOP-related assignments including instructional planning. There were, however, different degrees of improvement in their acquisition of the key concepts amongst the preservice teachers individually and by content area. Mathematics majors demonstrated the greatest improvement, while social studies and music majors were less able to apply the ideas into their instructional planning. There would be value in future research to explore these differences to determine how key concepts might be more broadly acquired. [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.]