Bipolar disorder (BD) is a mental health problem characterized by episodes of mania and depression which can lead to significant difficulties impairing one's daily functioning. Cross-sectional research has highlighted self-esteem and dysfunctional beliefs in those with this diagnosis, but there has been little research into how self-esteem and dysfunctional beliefs relate to symptoms of mania and depression over time. A secondary data analysis of a prospective cohort study was used. Forty patients with BD attending a community adult mental health service completed the Dysfunctional Attitudes Scale, Rosenberg Self-Esteem Scale, Brief Hypomanic Attitudes and Positive Predictions Inventory, Centre for Epidemiologic Studies Depression Scale, and Altman Self-Rating Mania Scale at two time points 4 months apart. Cross-sectional correlations revealed significant associations between elevated goal attainment dysfunctional beliefs and higher symptoms of mania; however, this did not hold over time. Elevated dependency-related dysfunctional beliefs and lower self-esteem were linked to higher symptoms of depression, and this relationship held over time. There was no impact of achievement-related dysfunctional beliefs on mood. Extreme appraisals were correlated with higher depression symptoms at baseline, but this did not hold over time. Findings suggest lower self-esteem and specific dysfunctional beliefs around dependency may precede symptoms of depression. Further research is required to further explore these associations. Elevated dysfunctional beliefs around dependency on others and lower levels of self-esteem may precede symptoms of depression in BD. Therapeutic interventions and relapse prevention targeting these psychological factors may help reduce the risk of depression relapse. © 2020 The British Psychological Society.