Although originally considered to be a disorder of childhood, attention deficit/hyperactivity disorder (ADHD) is increasingly being diagnosed for the first time in adulthood. Yet we know little about the social characteristics (race, gender, and social class) of those first labeled in adulthood, how these differ from those first labeled in childhood/adolescence, and whether the ADHD label is applied proportionately across social groups given ADHD symptomology. Using data from the National Longitudinal Study of Adolescent to Adult Health, the current research considers how typifications of ADHD affect application of the ADHD label in childhood/adolescence and in adulthood. Results indicate that even after controlling for ADHD symptoms, social characteristics are important predictors of the ADHD label in childhood/adolescence but are less influential in predicting ADHD labeling in adulthood. Additionally, results indicate the importance of race in moderating the association between childhood ADHD symptoms and application of the ADHD label throughout the life course.