We investigated the association of sleep quality with the Central Sensitization Inventory (CSI), pressure pain thresholds (PPT), temporal summation, and conditioned pain modulation (CPM) in 251 people with knee osteoarthritis, adjusted for sex, age, body mass index (BMI), anxiety-depressive symptoms, pain catastrophizing, fatigue, comorbidities, and radiographic severity. Overall, sleep quality was associated with changes in the CSI and PPT. However, when stratified by sex, only women had changes in sleep associated with the CSI, PPT, and CPM. Longitudinal studies should confirm these findings.