OBJECTIVE This study aims to assess the effectiveness of a 12-weeks self-management and exercise intervention to improve self-efficacy in older individuals with knee osteoarthritis (KOA) DESIGN: Randomised Controlled Trial. SETTING Four different community settings. SUBJECTS Eighty individuals aged 60 years or over with clinical and radiographic knee osteoarthritis. INTERVENTION The subjects were randomly assigned to (1) a combined self-management and exercise programme (treatment group) and (2) an educational programme (control group). MAIN MEASURES The primary outcome was self-efficacy and secondary outcomes were physical activity, health-related quality of life and skill-related physical fitness measures. RESULTS Sixty-seven participants, mean age 69.1 (5.8) years, completed the study: 32 in the control group and 35 in the treatment group. A significant group effect favourable to the treatment group was observed in the following variables: self-efficacy (F[2,64] = 9.2, p = 0.003), physical activity (F[2,64] = 43.6, p