In order to improve fuel efficiency in automobiles, engineers in the automotive industry have begun using lighter metals to replace steel in some external panel components. Aluminum alloy AA6111, a common choice for this application, can be improved through various physical processes. It has already been demonstrated that artificial aging significantly improves the strength characteristics of AA6111. In this study, the effect of natural aging at room temperature before artificial aging of AA6111 was investigated. Samples were solution heat treated, naturally aged at room temperature for various periods of time, and subjected to artificial aging. The hardness of each sample was measured throughout the aging process. The results show that peak hardness decreases with natural aging time, indicating that AA6111 body panels which are to be used on automobiles should be artificially aged as soon as possible after formation in order to maximize the beneficial effects of artificial aging.