We tested the feasibility and preliminary effectiveness of an acceptance and commitment therapy self-help intervention for grief and psychological distress in carers of patients in palliative care. Carers were randomised to the control group, which received treatment as usual, or the intervention group, which received treatment as usual plus an acceptance and commitment therapy–based self-help booklet and telephone support call. Questionnaires were completed at baseline, 1-month post-allocation and 6 months post-loss. Results indicated that the intervention was generally feasible and viewed as acceptable to carers. Preliminary effectiveness analyses showed at least a small effect in acceptance, valued-living, grief and psychological distress.