This study examined the relationship between balance confidence and function in older adults after knee-replacement surgery. Thirty-six adults (20 men and 16 women age 58–84 years) completed measures of balance confidence, general self-efficacy, and function. Results showed that participants with greater balance confidence had better functional performance and reported fewer difficulties with activities of daily living. General self-efficacy and age were not related to any of the functional measures. Women scored lower than men for all balance-confidence and function measures. These findings highlight the potential value of studying balance-related self-efficacy beliefs in people with knee replacements. Longitudinal studies are now needed to determine whether a change in balance confidence is associated with a change in function and to further explore gender differences.