The present research investigated the relationships between loneliness and emotional, physical, and cognitive wellbeing in young and older adulthood. Self-report questionnaires were administered to 101 young and 95 older adults. Young adults reported slightly higher loneliness than older adults. Overall, young and older participants who reported the greatest amount of loneliness experienced significantly less positive affect than those reporting the least amount of loneliness. However, higher levels of loneliness were related to increased negative affect only within the older adult group. Increased loneliness was also correlated with poorer reports of physical health exclusively in older adults. No relationships were found between loneliness and fluid cognitive ability or loneliness and information processing style. The exacerbated negative impact of loneliness in older adults is interpreted as an effect of age-related changes in motivation toward socioemotional goals related to the limited future time perspective of older individuals.