The present study aims to examine the effects of the MindfulTEA program, an Mindfulness-based Interventions (MBIs) specifically designed for adults with Autism Spectrum Disorder (ASD) and Intellectual Disability, to reduce behavioural problems. MBIs are effective in improving well-being in people with high-functioning ASD, but little is known about the impact of the MBIs on people with ASD and intellectual disability associated. Fourteen adults (age 18 to 44) with ASD and intellectual disability participated in the program. Results showed a significant decrease in self-injurious and aggressive/destructive behaviours after the MBI. Stereotyped behaviour did not show significant change. Results suggest that the MindfulTEA program could effectively reduce some types of behaviour problems in people with ASD and intellectual disability. MBIs could be a useful alternative to traditional behaviour management interventions for reducing behaviour problems in this population.