Background Maladaptive perfectionism is a transdiagnostic risk and maintaining factor for a range of mental health conditions, including bipolar disorder (BD). Self-compassion represents a potential protective factor against maladaptive perfectionism, however no studies to date have examined the relationship of these constructs in BD. The aim of the present study was to examine associations between maladaptive perfectionism, self-compassion and symptoms among individuals with BD. Methods Baseline data were collected from 302 participants with a DSM-IV diagnosis of BD participating in an international randomised controlled trial. Participants completed measures of maladaptive perfectionism, self-compassion, symptom severity and emotion regulation difficulties. Clinician-administered measures of depression and mania severity were additionally collected. Correlation and mediation analyses were conducted. Results Maladaptive perfectionism was positively associated with depression, anxiety and emotion regulation difficulties. Lower levels of self-compassion correlated with greater self-reported depression, anxiety and emotion regulation difficulties. Self-compassion partially mediated relationships between maladaptive perfectionism, depression, anxiety and emotion regulation difficulties. Limitations The cross-sectional design limits conclusions about causal relationships between study variables. Results may not be generalizable to other BD populations. The role of maladaptive perfectionism and self-compassion in elevated mood states of BD remains unclear. Conclusion Self-compassion represents one mechanism through which maladaptive perfectionism influences symptoms of depression, anxiety and emotion regulation difficulties in BD. Self-compassion represents a modifiable treatment target; individuals with BD exhibiting maladaptive perfectionistic tendencies may benefit from interventions fostering self-compassion.