Sensory integration based paediatric occupational therapists working in schools commonly function with a dual role of providing the child with therapy to assist the child to function optimally as well as act as consultants in assisting teachers to develop strategies to help promote the classroom performance of students with sensory processing difficulties. A single-group pre test post test quasi-experimental research design was used in this pilot study on a convenient sample of 11 participants to explore the effects before and after exposure to the intervention of a sensory diet on the in-seat behaviours of the child and determine whether the desirable sensory input is effective in improving the performance of children with sensory processing difficulties during a handwriting lesson. The behaviours showing the highest trend of improvement in the hypothesized direction included less distractibility and trend of work ethos related behaviours (not giving up easily and completing the task; being less impulsive, not working too fast, better planning; better able to initiate and carry tasks out independently). Trends of various in-seat behaviours (restless, overactive and fidgety, disorganized on self and in his work, difficulty in getting down to his work, slow to complete a task) to regress in the hypothesized direction were also noted. Descriptive and statistical analysis was performed to examine trends in changes of pre- and post-intervention behavioural scores. The data were also analysed using Poisson’s regression to the normal distribution to calculate p values (using a chisquared distribution) to compare the number of observations in a period of time intervals. Implications of the results of the study for therapists working with students with sensory processing difficulties and their teachers are discussed.