Background: Previous research suggests benefits of targeting beliefs about the unacceptability of emotions in treatment for irritable bowel syndrome (IBS). Aims: The current study developed and tested an intervention focusing on beliefs and behaviours around emotional expression. Method: Four participants with IBS attended five group sessions using cognitive behavioural techniques focusing on beliefs about the unacceptability of expressing emotions. Bi-weekly questionnaires were completed and a group interview was conducted. This study used an AB design with four participants. Results: Averages indicate that participants showed decreases in beliefs about unacceptability of emotions and emotional suppression during the intervention, although this was not reflected in any of the individual trends in Beliefs about Emotions Scale scores and was significant in only one individual case for Courtauld Emotional Control Scale scores. Affective distress and quality of life improved during follow-up, with only one participant not improving with regard to distress. Qualitative data suggest that participants felt that the intervention was beneficial, referencing the value in sharing their emotions. Conclusions: This study suggests the potential for beliefs about emotions and emotional suppression to be addressed in cognitive behavioural interventions in IBS. That beliefs and behaviours improved before outcomes suggests they may be important processes to investigate in treatment for IBS.