In the United States, the growth of cultural and linguistic diversity of the nation's population brings students from a wide range of backgrounds to America's schools. This research investigated the perceptions of English as a New Language (ENL) and General Education (GE) co-teachers in a grades 3-5 setting. The study included the perceptions of one another's roles, strengths, and areas for improvement in co-teaching academic language and content to English language learners (ELLs) in the GE classroom. Co-teaching has been one of the methods used to deliver an inclusive service to English Language Learners. Theories of social constructivism and cooperative learning guided this study, which approaches co-teachers' perceptions as a function of how they make meaning of their social interaction and experiences (Vyogotsky, 1978; Villa, Thousand, & Nevin, 2004). The study used a qualitative case study design which included focus groups at one elementary school site. The focus groups included 4 General Education teachers and 4 ENL teachers in an open-ended dialogue regarding co-teaching. In addition, professional development needs and offerings were reported. The findings highlight the areas of convergence and divergence in ENL and GE teachers' perceptions as co-teachers of ELLs in the GE classroom. Overall, ENL and GE teachers appeared to have a general understanding of one another's roles, yet some perceptions diverged with regard to sharing responsibilities and whether the GE teacher was the "master instructor". Further, this study concludes that despite availability of some common planning time, co-teachers frequently desired to improve the quality and quantity of their co-planning, co-teaching and professional development. The analysis of data concluded that both ENL and GE co-teachers sought increased collaborative time, partnership, and professional development offerings, which created the Foundational themes of the study. The study concludes with a discussion of implications for practice geared towards school administrators and teachers, who want to support ESL and GE co-teachers, or are looking to implement a co-teaching model in their program. The discussion also addresses the implications for ESL and GE teachers whose co-teaching practice may benefit from the findings of the study. Finally, recommendations for future research from this study are offered. [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.]