OBJECTIVE: Patellar taping is a conservative treatment that may reduce patellar malalignment and pain in people with patellofemoral joint osteoarthritis (OA). This study aimed to compare patellar alignment in people with and without patellofemoral joint OA and to evaluate immediate effects of patellar taping on patellar alignment and pain in people with patellofemoral joint OA. METHODS: Patellar malalignment was measured from magnetic resonance imaging (MRI; 15 degrees knee flexion) in 28 individuals (14 with patellofemoral joint OA and 14 asymptomatic, age-matched controls). In the patellofemoral joint OA group, MRI data were collected in 2 randomly allocated conditions (tape and no tape). Patellar alignment indices were measured from deidentified axial scans by 1 examiner. Pain during squatting was recorded in the 2 conditions (tape and no tape). RESULTS: People with patellofemoral joint OA exhibited greater lateral displacement and bisect offset compared with controls (P < 0.001). Lateral patellar tilt angle did not differ between groups. In the patellofemoral joint OA group, patellar tape resulted in a significant lessening of lateral alignment, with reduced lateral displacement (P = 0.028) and increased lateral patellar tilt angle (P < 0.001). Mean pain during squatting decreased with patellar tape by 15 mm on a 100-mm scale (P = 0.045). CONCLUSION: Patellar tape may reduce malalignment and pain associated with patellofemoral joint OA.