Osteoarthritis is the most common form of arthritis and a leading cause of disability worldwide, largely due to pain, the primary symptom of the disease. The pain experience in knee osteoarthritis in particular is well-recognized as typically transitioning from intermittent weight-bearing pain to a more persistent, chronic pain. Methods to validly assess pain in osteoarthritis studies have been developed to address the complex nature of the pain experience. The etiology of pain in osteoarthritis is recognized to be multifactorial, with both intra-articular and extra-articular risk factors. Nonetheless, greater insights are needed into pain mechanisms in osteoarthritis to enable rational mechanism-based management of pain. Consequences of pain related to osteoarthritis contribute to a substantial socioeconomic burden.