Retrospective reports of family environments are often the only way to collect the data concerning the influence of a child’s experience in the family on later development. However, the accuracy of retrospective measures can be problematic because of social desirability or potential failures of memory. The purpose of this study is to compare retrospective and prospective measures of family environment. In this unique study, 198 parents and 241 adolescent children (mean age 15.7) described their family environment, and then 25 years later, completed retrospective reports. We test the effects of memory, positivity, gender, and generation on retrospective reports, as well as testing the ability of prospective and retrospective measures to predict adult well-being and adult–child/elder–parent relationships. Results show moderate correlations of 0.30–0.45 between prospective and retrospective measures. In examining the relative effectiveness of prospective and retrospective measures to predict later life outcomes, we find that retrospective reports of the family environment most validly capture influences on the child in domains of strong emotional content but are less successful in cognitive domains.