Adult English language learners are hungry for pronunciation instruction that helps them to “crack the code” of speaking intelligible English (Derwing, 2003). Research indicates benefits of pronunciation instruction with adult learners, yet many teachers believe they lack the knowledge and background to make sound instructional decisions (Baker, 2014). This article looks at a professionaldevelopment initiative in which 12 practicing adult English language teachers participated in a 5-week study circle on researchinformed, integrated pronunciation instruction. The study circle included readings on current research, workshops on teaching strategies and techniques, speech-sample analyses, classroom implementation tasks, and peer observations. Throughout the process, data were gathered including pre- and post-surveys, speechanalysis logs, and a delayed focus group session to evaluate the impact of participation on teaching practices. Findings indicate an increased ability to diagnose and accurately describe pronunciation issues, integrate pronunciation instruction into the existing curriculum and classroom routines, and apply research-informed practices within the classroom.