The purpose of this study is to explore the views of autistic adults on randomised controlled trials, specifically on processes such as randomisation and blinding, to understand the barriers and facilitators for recruiting autistic people to randomised controlled trials involving medications. We conducted one-to-one interviews with 49 autistic adults. Interviews were audio-recorded and analysed thematically. The participants found randomised controlled trial processes acceptable and linked positive attitudes towards randomised controlled trial participation to autistic peoples' heightened sense of fairness and preference for evidence-driven knowledge. However, randomised controlled trial designs may be incompatible with a (1) preference for a controlled predictable world, (2) perceived vulnerability at physical and mental health levels and (3) history of misunderstanding and exclusion, crucially from healthcare professionals. Suggestions that emerged from our findings include efforts to co-produce research to nurture trust and adapting communication practices to improve access to trials. Autistic people are a highly motivated group to work with research teams to mitigate barriers to randomised controlled trial participation. We explored what psychosocial determinants play a role in the acceptability of randomised controlled trials to test interventions to improve quality of life and mental health in autistic adults. The study provides useful information that may help the design and conduct of more accessible trials with and for the autistic community.