OBJECTIVE Intraarticular hyaluronic acid injection (IAHA) is a popular treatment for knee osteoarthritis (OA). This study investigates whether depression, anxiety, and pain affect self-reported knee function in geriatric OA people who have received IAHA. METHODS Through convenience sampling, 102 geriatric patients (mean age = 70.91 ± 7.19; 28 males) with knee OA who had undergone IAHA participated in this study. All participants self-reported depression using the Geriatric Depression Scale (GDS), anxiety using the State-Trait Anxiety Inventory (STAI), knee function using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the International Knee Documentation Committee subjective knee evaluation form (IKDC), and pain severity using the Visual Analogue Scale (VAS). They completed the aforementioned questionnaires at baseline before injection and then again at 2-, 4-, and 6-month follow-ups. RESULTS Depression was significantly associated with IKDC, WOMAC physical function subscale, and total WOMAC scores. Anxiety was only significantly associated with the WOMAC pain subscale score. Pain severity was significantly associated with IKDC, WOMAC stiffness subscale, WOMAC physical function subscale, and total WOMAC scores. CONCLUSIONS Given that depression negatively affected patient-reported knee function among geriatric OA patients who had undergone IAHA, further attention should be paid to the depressive status of this population.