Background Effective group psychological interventions in bipolar disorder are rare. In this study, we present “metacognitive training (MCT) for bipolar disorder”—an adaption of a group intervention that has proven effective in other severe psychiatric disorders. MCT is a structured, interactive approach that addresses cognitive biases, social cognition, and self‐esteem. In this pilot study, we investigated psychosocial functioning as primary outcome measure, as well as the feasibility of MCT and its acceptance among bipolar patients. Methods Thirty‐four outpatients with bipolar disorder were recruited. Inclusion criteria were euthymia and psychosocial functioning with a score >11 assessed by the Functional Assessment Short Test. The subjects received eight weekly MCT sessions. Before and after the intervention, psychosocial functioning, quality of life (QoL), and patient views were assessed. Results Patients improved significantly in global psychosocial functioning, with a large effect size from baseline to post‐treatment. Over the intervention period, patient QoL improved significantly in terms of their physical health, however not for other QoL subdomains. Treatment adherence was 80%, and patients' appraisal of the training was positive. Limitations As this study lacks a control group, it is not possible to ascertain whether the positive treatment effects are attributable to MCT. Additionally, it is unclear whether gains in psychosocial functioning would have been maintained long term. Conclusions This pilot trial conclusively shows that MCT is feasible and provides preliminary evidence for both the acceptance and efficacy of MCT. Further studies with larger samples and control condition will be necessary to build on these findings.