Pupils with intellectual disabilities are one of the most bullied groups in the school system and in local communities. Moreover, young people also play a significant role in hate crimes against people with intellectual disabilities of all ages beyond the school gates. This paper describes the development of a research informed program of lessons for children in mainstream secondary schools, aimed at counteracting bullying towards people with intellectual disabilities by promoting empathy and more positive attitudes towards them. A literature review, a review of current practice, and the experiences and views of young people with intellectual disabilities and their families all contributed to the development of the program. Data from subsequent piloting and feasibility work were used to finalize the program which consists of the following five lessons concerning: (i) difference and disability, (ii) an understanding of intellectual disability, (iii) the nature and impact of disablist bullying towards people with intellectual disabilities, and (iv) opportunities for inclusion. One conclusion from this work is that that there needs to be further research to explore the impact of school-based interventions, promoting an understanding of people with intellectual disabilities, in the wider community. Teachers delivering the lessons may have greater influence than transitory campaigns to counteract bullying and promote positive attitudes towards people with intellectual disabilities. However, a first step is to ensure that teachers delivering the lessons have an understanding of people with intellectual disabilities.