The experience of psychosis can lead to depression, anxiety and fear. Acceptance and Commitment Therapy (ACT) facilitates individuals to accept difficult mental experiences and behave in ways that are consistent with personally held values. This study was a single (rater) blind pilot randomised controlled trial of ACT for emotional dysfunction following psychosis.Twenty-seven participants with psychosis were randomised to either: ten sessions of ACT plus treatment as usual (TAU) or TAU alone. The Hospital Anxiety and Depression Scale, Positive and Negative Syndrome Scale, Acceptance and Action Questionnaire, Kentucky Inventory of Mindfulness Skills and Working Alliance Inventory were used. Individuals were assessed at baseline and 3 months post-baseline. The individuals randomised to receive ACT found the intervention acceptable. A significantly greater proportion of the ACT group changed from being depressed at time of entry into the study to not being depressed at followup. The ACT group showed a significantly greater increase in mindfulness skills and reduction in negative symptoms. Results indicated that individuals randomised to ACT had significantly fewer crisis contacts over the study. Changes in mindfulness skills correlated positively with changes in depression. ACT appears to offer promise in reducing negative symptoms, depression and crisis contacts in psychosis.