There is little guidance for teachers about how best to teach young chil- dren in SEN schools in Wales. Recent research has shown that teaching based on Applied Behaviour Analysis (ABA) is an effective model for Foundation Phase and Key Stage 1 in maintained special needs schools (Foran et al., 2015; Pitts, Gent and Hoerger, 2019). The current study replicated the model and included curriculum measures (P Scales) typically used by educators and the validated, normed-assessments (MSEL and VABSII) commonly used by researchers. Following the classroom-based ABA model implementation, participants made significant gains on curriculum measures and normed-assessments. The data from all assess- ments showed statistically significant gains with medium to large effect sizes. This study demonstrates how teachers can utilise behaviour analytic strategies to prepare students with readiness for learning skills essential for accessing the curriculum. This study outlines how techniques based on the principles of ABA can complement educational provision in maintained SEN schools in Wales.