Previous research suggests that for people living with chronic pain, pain expectancy can undermine access to adaptive resources and functioning. We tested and replicated the unique effect of pain expectancy on subsequent pain through 2 daily diary studies. We also extended previous findings by examining cognitive and affective antecedents of pain expectancy and the consequences of pain expectancy for daily social enjoyment and stress. In study 1, 231 individuals with rheumatoid arthritis completed 30 end-of-day diaries. Results of multilevel structural equation model showed that controlling for today's pain, pain expectancy predicted next day pain. In study 2, diary assessments of affective, cognitive, and social factors were collected during the morning, afternoon, and evening for 21 days from a sample of 220 individuals with fibromyalgia. Results showed that both positive affect and the extent to which pain interfered with daily activities in the afternoon predicted evening pain expectancy in the expected direction. However, negative affect and pain coping efficacy were not associated with pain expectancy. Consistent with study 1, more than usual evening pain expectancy was related to greater next morning pain. We also found that next morning pain predicted next afternoon social enjoyment but not social stress. The findings of these 2 studies point to the importance of promoting positive affect and reducing pain expectancy as a way of decreasing the detrimental effect of chronic pain on enjoyable social experiences.