Background <p>Self-management is a critical component of care of autoimmune inflammatory arthritis, but current measures do not address all five core self-management domains. We aimed to develop and evaluate a novel questionnaire of self-management efficacy in arthritis.</p> Methods <p>A rapid review was conducted to identify existing self-management questionnaires for chronic disease and arthritis. Information on item focus, format, scoring and psychometric attributes was extracted. Results were used to inform development of a draft questionnaire with 20 items across five domains: medication, exercise, diet, smoking cessation and wellbeing. Feedback on comprehensibility, perceived usefulness and comprehensiveness from a convenience sample of people with inflammatory arthritis (<i>n</i> = 12), and a sample of medical clinicians (<i>n</i> = 8), was used to refine questionnaire instructions and items. The refined measure was completed online by 135 people with inflammatory arthritis enrolled in the A3BC biobank (<i>n</i> = 392) and data were used to assess structural validity (exploratory factor analysis), internal consistency (Cronbach alpha), and 2-week test-retest reliability (Intraclass Correlation Coefficient, ICC; <i>n</i> = 112).</p> Results <p>Exploratory factor analysis supported a multidimensional structure. Each subscale was strongly unidimensional when examined independently. The items demonstrated strong internal consistency in all five subscales of self-management (Cronbach alpha 0.92–0.98). The test-retest reliability was acceptable with subscale ICCs 0.61–0.89.</p> Conclusion <p>The novel Self-Management in Arthritis (SMART) questionnaire incorporates 20 items to assess efficacy for five domains of self-management of arthritis. Preliminary psychometrics are promising with unidimensional subscales, strong internal consistency, and acceptable test-retest reliability. Further evaluation can contribute to the use of SMART in research or clinical practice settings.</p>