Interventions to increase the endorsement of the growth mindset (the belief that intelligence can be improved with effort) have been successfully implemented in schools. However, they rarely target children and young people with special educational needs and/or disabilities (SEND), a group who are more likely to endorse a fixed mindset, experience lower academic self-concept and academic resilience, and be at risk of negative stereotyped attitudes. This quasi-experimental study implemented a 10-week PSHE programme as well as dedicated lessons with adapted classroom practices, for example, task framing and feedback, to promote the growth mindset message to young people with SEND (N = 18). Analyses of pre- to post-intervention measures demonstrated moderate evidence for the intervention having increased students' endorsement of the growth mindset, as well as anecdotal evidence for increased academic self-concept, academic resilience and positive attitudes to disability. However, these effects were not sustained in follow-up measures conducted 7 weeks post-intervention. The intervention did not improve students' academic performance. Although preliminary, findings demonstrate the viability of growth mindset interventions for children and young people with SEND, but suggest that interventions should be maintained for longer-lasting effects.