In the current study, a Dutch whole school Positive Education Programme (PEP) was investigated. PEP is a bottom-up programme, aimed at shifting teacher's attention from solely focusing on learning outcomes towards a more comprehensive approach that takes the wellbeing and engagement of students during classes into account. PEP was investigated through a clustered quasi-experimental trial. Four primary schools, 639 pupils, were included, of which two were allocated to PEP. Multilevel analyses showed no significant differences on any of the outcomes. However, the data indicated a trend towards more engagement in the intervention schools (p = 0.09). Also, at post-measurement, the proportion of sufficiently engaged students was significantly higher in the intervention schools. Although it seems too premature to draw conclusions regarding the effectiveness of such a whole school approach, the findings on engagement are promising and have the potential to engender a wide range of other beneficial outcomes.