A single case experimental design with multiple baselines was employed to explore the relationship between a solution focused intervention delivered by school staff and the externalising behaviour of four primary school pupils. The intervention took place over four to five sessions, which were delivered by non-specialist school staff with the use of training, supervision, and a manual. Observations of a specific positive behaviour were carried out both before and during the intervention, which were then analysed through visual and statistical analysis. A pre and post intervention questionnaire measure of pupils' externalising behaviour was collected. For each participant, one videoed session was used to explore the fidelity of the intervention to the manual. Analysis of observations of behaviour showed a significant increase in a specific positive behaviour for three of four participants. A measure of pupils' externalising behaviour showed a significant reduction for two of the eight questionnaires collected. Video analysis suggested variation of fidelity across participants. This research provides tentative support for specific outcomes from a solution focused intervention, when delivered by non-psychologists who are provided with appropriate support. It has also been found that non-specialist school staff practitioners were able to deliver the intervention through applying elements from a manual to have a positive impact on a specific behaviour for three of four participants. There is a need for further high quality research to establish the effectiveness of solution focused interventions when delivered by non-specialists with the use of consistent intervention and outcome measures.