OBJECTIVE: 'DASH for Asthma' (n 90) was a 6-month randomized controlled trial that demonstrated potential benefits of a DASH (Dietary Approaches to Stop Hypertension) behavioural intervention for improving diet quality and asthma control by comparing intervention to usual care in adults with uncontrolled asthma. The present study examined acceptability and feasibility of the intervention from the perspective of intervention participants and lifestyle coaches. DESIGN: Grounded in Social Cognitive Theory, the 3-month intensive stage, including three individual and eight group sessions, focused on diet modifications and behavioural self-regulation. The 3-month maintenance stage contained telephone consultations. Participants and lifestyle coaches completed surveys including 5-point Likert scales and open-ended questions. We analysed data using descriptive and inductive content analyses. SUBJECTS: Forty-six intervention participants (survey response rate was 65-72 %) and two lifestyle coaches. RESULTS: Participants and lifestyle coaches were highly satisfied (all mean ratings >4) with individual and group sessions. Participants identified mastery of knowledge and skills (awareness, goal setting, self-monitoring, problem solving), social learning (class members sharing experiences and ideas) and good coaching skills (reflective listening, empathy, motivational counselling) as important contributors to self-efficacy and programme satisfaction. Participants also valued personalized feedback received in individual sessions. Lifestyle coaches viewed participant engagement as a facilitator to effective sessions. Finally, participants and lifestyle coaches identified food tasting as beneficial for observational learning and facilitation of participant engagement. High class attendance and self-monitoring rate also reflected the high engagement among participants. CONCLUSIONS: The DASH behavioural intervention was feasible and highly acceptable to participants with uncontrolled asthma and lifestyle coaches.