A toolkit approach to professional development is frequently used to assist teachers of English language learners (ELLs), wherein teachers are provided a grab bag of activities and strategies to implement in their classrooms. However, today's heightened language demands call for teachers to develop teacher language awareness (TLA), a language lens that teachers use as a filter for text and material selection, instructional planning, and responsive teaching. Deeper professional development experiences are required to help teachers develop knowledge and expertise in the three domains of TLA: the user domain, the analyst domain, and the teacher domain. This article provides justification for TLA development, explanations of each TLA domain, plus concrete professional development ideas that can be implemented at a school, institution, or district level. doi: 10.1002/tesj.223Educators in both English as a second language (ESL) and English as a foreign language (EFL) contexts require continued professional development to stay abreast of new research and pedagogical innovations in the TESOL field. This article is directed at those TESOL educators who belong to the content-based instruction community of participation, that is, language teaching environments wherein content and language are taught simultaneously. Often referred to as CBI (for content-based