This study examines tensions in the grammar teaching beliefs and practices of three practising teachers of English working in Turkey. The teachers were observed and interviewed over a period of 18 months; the observations provided insights into how they taught grammar, while the interviews explored the beliefs underpinning the teachers' classroom practices. Drawing on the distinction between core and peripheral beliefs, the analysis indicated that, while at one level teachers' practices in teaching grammar were at odds with specific beliefs about language learning, at another level, these same practices were consistent with a more generic set of beliefs about learning. The latter, it is hypothesized, constituted the teachers' core beliefs and it was these, rather than the more peripheral beliefs about language learning, that were most influential in shaping teachers' instructional decisions. It is argued that attention to the relative influence of core and peripheral beliefs on teachers' practices allows for more complex understandings of tensions in teachers' work. Claims are also made here for the benefits of grounding the study of tensions between stated beliefs and classroom behaviours in the qualitative analyses of teachers' actual classroom practices. Some implications of this study for language teacher education are also discussed. © 2009 Elsevier Ltd. All rights reserved.