Aim: This study sought to identify the impact of a maths intervention aimed at enhancing performance, self-concept and self-regulation, while reducing negative emotional responses. Method: A quantitative, between-group repeated-measure experimental design was used to investigate differences between the groups over time. One-hundred-and-forty-four Year 4 pupils (mean age 8.09 years) from eight schools were matched and randomly allocated to intervention or waiting-list control groups. Trained Teaching Assistants delivered the intervention in small groups for four weeks. Performance, self-regulation, self-concept and anxiety in maths were measured pre- and post-intervention. Findings: Mixed ANOVA found a significant difference in maths performance and in the strategising and focusing sub-behaviours of self-regulation. No significant differences in maths anxiety and self-concept were established, although exploratory investigation identified a significant impact on males' maths self-concept. Limitations: The placebo effect, variable delivery, alongside appropriate maths anxiety and self-regulation measures in this age group, potentially influenced the results. Conclusions: The intervention indicates promising results with respect to maths performance; however further refinements of the affective elements are proposed. The negative relationship between maths self-concept and anxiety is discussed and practice implications are highlighted.