This article reports on a study examining second language (L2) teachers' understanding of speech fluency and their self-reported classroom practices for promoting it. Qualitative and quantitative data collected from 84 L2 teachers in England were analysed to answer the research questions. In addition to the descriptive statistics and lexical frequency analysis used to explore teacher understanding of fluency, Rossiter, Derwing, Manimtim and Thomson's (2010) framework was employed to analyse the teachers' reported classroom practices. The results suggest that teachers often define fluency in a broad sense, with many using fluency and speaking ability interchangeably. Similarly, a large majority of the activities reported by the teachers were useful for enhancing speaking practice rather than focusing on fluency specifically. The findings underline the interaction between teacher understanding and their methodology (Borg, 2003), and highlight a mismatch between what fluency research recommends and what teachers do in class. Though the study highlights the complex and multifaceted nature of L2 oral fluency, we argue that adopting a narrower understanding could help teachers take a more active and practical approach to promoting fluency in the classroom.