The effective management of inflammatory bowel disease (IBD) requires complex self-management behaviors. Both patient activation (the degree to which patients are willing and able to engage in care) and self-efficacy (one's confidence in performing certain behaviors) are thought to play an important role in chronic disease self-management, but patient activation is a broad concept that can be more difficult to precisely target than self-efficacy. We aimed to describe the relationship between patient activation, self-efficacy, and the burden of IBD on patients' daily lives. Patients with IBD were recruited from a single center to complete a survey including the Patient Activation Measure (PAM-13®), the IBD Self-Efficacy Scale (IBD-SES), and an IBD-specific patient-reported outcome measure. Using multivariable linear regression, we examined the relationship between IBD burden, self-efficacy, and patient activation, adjusting a priori for age, gender, IBD type, IBD medications, active corticosteroid use, anxiety, and depression. We performed a post-hoc mediation analysis to examine self-efficacy as a potential mediator in the relationship between patient activation and the burden of IBD on patient's daily lives. A total of 132 patients with IBD completed the survey (59% Crohn's disease, 41% ulcerative colitis, 52% female). Higher levels of patient activation and higher levels of self-efficacy were each associated with lower IBD burden (patient activation: ß = -1.9, p < 0.001, self-efficacy: ß = -2.6, p < 0.001). Post hoc mediation analysis confirmed that the relationship between patient activation and daily IBD burden was mediated by self-efficacy (Average Causal Mediation Effect = -1.00, p < 0.001, proportion mediated = 0.62, p < 0.001). The relationship between patient activation and IBD burden is highly mediated by self-efficacy, suggesting that self-efficacy could be a more precise target for intervention. Future studies could focus on targeting self-efficacy to build individuals' confidence in IBD self-management and testing of IBD-tailored self-management programs to ultimately improve disease outcomes.