Background: Promotion of a healthy lifestyle for individuals with mild intellectual disabilities is important. However, the suitability of behaviour change techniques (BCTs) for these individuals is still unclear. Methods: A Delphi study was performed using the Coventry, Aberdeen & LOndon -- REfined (CALO-RE) taxonomy of BCTs (n = 40). Health professionals (professional caregivers, behavioural scientists, health professionals, intellectual disability physicians) participated in an online survey to determine whether BCTs were suitable or unsuitable. Comments from participants were analysed qualitatively. Results: Consensus was reached for 25 BCTs out of 40. The most suitable BCTs were barrier identification (97%), set graded tasks (97%) and reward effort towards behaviour (95%). No significant differences were found for intergroup effects. Conclusion: Regardless of their position and education level, health professionals reached consensus about the suitability of BCTs for individuals with mild intellectual disabilities. Increased use of these BCTs could result in more effective promotion of a healthy lifestyle.