This investigation studied a cluster of six primary schools during a period when they undertook a classroom-based early intervention initiative aimed at literacy standards. The schools were situated in, or close to, an urban area of multi-disadvantage. The aim was to discover more about the impact of early intervention in literacy for socio-economically disadvantaged children; the process of school involvement in the intervention and participants’ experiences and perceptions of any change processes that took place. A mixed-method research design was employed where both quantitative and qualitative methodologies were used. The study was longitudinal in design. The sample numbered 665 children and 57 adult participants in total. The intervention had the most positive impact for children tested on entry to Primary 2. During their first year at school the more socio-economically advantaged children were more likely than their less advantaged peers to have benefited from involvement in the intervention. It is possible that children needed to have reached a certain point in the continuum of literacy learning to benefit. Arguably, this finding coupled with the differential on entry to school in terms of their baseline scores has important implications for the nature of literacy intervention at the Primary 1 stage. Small group and individual approaches facilitated by the recruitment of teams of personnel working within the classroom setting, an approach initiated by schools in this study, may be a strategy worthy of development and further research. The metacognitive process of ‘thinking about thinking’ (Jacob and Paris, 1987) was apparent in children’s accounts. A range of evidence suggests that the children had a developing understanding of the purpose of their literacy instruction and the benefits of learning to read and write: a finding that seems to contradict the conclusions of earlier studies. There was evidence to suggest that aspects of multi-level change had taken place during the intervention. Some changes were planned for as part of the intervention, while others were unexpected, emerging as the dynamic of the intervention got underway. It seems that collaboration between a cluster of schools and external agents may be a particularly powerful combination that strengthens and supports individual headteacher’s capacity for initiating and implementing change.