Irish education is currently witnessing a fundamental shift in focus from an emphasis on curriculum revision, professional development and policy implementation to one of review, with the concomitant effect that issues of evaluation and assessment are increasingly high on the agenda. This is evidenced by the publication in recent years of a series of evaluation reports which, in addition to identifying successes achieved, have highlighted a number of related iterative weaknesses in the system that continue to thwart progress. One is the apparent lack of assessment literacy which has been attributed mainly, but not exclusively, to teachers. Another is the growing body of international evidence suggesting that pedagogical practices in schools serving disadvantaged children are qualitatively different to those found in more advantaged settings. Finally, there is the evidence that low levels of literacy persist in Ireland, despite significant investment and innovation. In responding to these challenges, this study examined the potential of a teacher learning community (TLC) as a vehicle of professional development, to bring about changes in teachers’ understanding and use of Assessment for Learning (AfL), in order to improve the reading competency of a cohort of children attending a designated disadvantaged, junior school, in the Republic of Ireland. Employing a partially mixed, concurrent, equal status, quantitative/qualitative design, the study investigated three research hypotheses pertaining to (1) children’s reading achievement, (2) their motivation to read/employment of AfL strategies when reading and (3) teachers’ knowledge, skills and attitudes of/to AfL. Outcomes from the quantitative data with respect to the first two hypotheses indicated that there were no statistically significant differences in mean reading achievement between control and experimental groups following the intervention, although significant differences were found for reading strategies. The qualitative data relating to the third hypothesis revealed that important changes had occurred in teachers’ attitudes and classroom practice over the duration of the project. The study concludes by drawing attention to the potential of a TLC, reconceived as a boundary zone, to challenge the traditional balkanisation of teachers’ working lives.