Osteoarthritis (OA) is one of the most common diseases and one of the leading causes of disability in the world. People with OA frequently experience sleep disturbances, primarily due to pain. Although insomnia is a known consequence of OA, recent studies have shown that it may also worsen clinical pain by interfering with the body's responses to painful stimuli. This study will evaluate the effectiveness of behavioral treatments for insomnia in reducing sleep disturbances, thereby reducing clinical pain in people with knee OA. The study will test whether improvement in clinical pain are mediated by changes in certain types of pain processing.