||Content-based instruction (CBI) aims to develop students’ content and language knowledge as well as their ability to use learning strategies to become autonomous learners. It is a language teaching methodology that uses content as the organizing principle and makes a dual commitment to both language and content objectives. Through a three-cycle action research project, this M.A. thesis investigated teacher and learner perceptions of a content and language integrated course in an English as a foreign language (EFL) environment. As the teacher/researcher in this project, I designed and taught the CBI course at a private English center in Niterói, Brazil. Learner data were obtained from initial questionnaires, student journals, and oral interviews in Cycles 2 and 3, and teacher data were obtained from teaching journals and videotaped lessons in the three cycles. Learner data indicated that some participants recognized the integration of language and content during the course and appreciated CBI methodology. Other participants had expectations for a traditional language course and were not able to recognize the integration of content and language. Although content was used as the organizing principle in the course, some learners paid little attention to the content and expressed a desire to improve their language skills, not realizing that it was possible to do both. Furthermore, some participants revealed that learning vocabulary derived from the content and vocabulary-learning strategies (VLSs) were beneficial despite the difficulty of some strategies. Although participants identified the importance of the content being taught (i.e., culture and specifically, intercultural tolerance), they did not show tolerance toward some aspects of American values and ideas during in-class activities. Teacher data showed that CBI methodology in Cycles 2 and 3 promoted a deeper understanding of content. As my own knowledge of the course content deepened, I realized that I was also able to use content resources more appropriately. Based on an analysis of qualitative data, I concluded that course design improved through the three cycles. Additional modifications to course design in the future would allow for more opportunities to target strategies and promote the gradual development of intercultural communication, tolerance, and acceptance.