Recent global developments have intensified the use of English as a lingua franca (ELF), the principal means of communication employed among speakers of different linguistic backgrounds to interact worldwide. Consequently, there has been a growing interest in the pedagogical implications and applications of ELF in language teaching and learning. Few works, though, have investigated the influence of ELF in bilingual education such as in Content and Language Integrated Learning (CLIL). The current paper describes the design and implementation of a CLIL + ELF observation tool that was used to study a pilot CLIL program in Taiwan and to anticipate CLIL teachers’ training needs. The data collected from the rubric were contrasted with several unstructured interviews. The rubric contains 10 criteria developed from previous CLIL and ELF studies including: learners’ L1 and L2 proficiency; teachers’ L2 proficiency; teachers’ ability to reflect upon their practice; their familiarity with CLIL and ELF methodologies; and the school’s commitment to bilingual education and language policy considerations. Using these criteria, the researchers identified many positive results such as teachers’ growing familiarity with CLIL and their use of class management language, content-related language, and academic communication. The study also suggests areas for improvement such as the need for teacher training regarding ELF.