Recent research has highlighted the critical problem of high rates of "disconnected youth"--youth and young adults who are neither employed nor in school. Practitioners, scholars, policymakers, and a range of stakeholders express mounting concern that disconnected youth are a societal burden that costs countries trillions of dollars. This phenomenon could threaten social cohesion and social development, in addition to costing large amounts of money in the forms of foregone labor productivity and tax revenues and increased incarceration and social services uptake rates. Whereas other studies explore disconnection among a cross-sectional sample of U.S. young adults, we set out to document the longitudinal education and employment pathways of a nationally representative cohort of U.S. millennial young adults from approximately age 16 to age 26. The results of this study highlight that both socioeconomic status (SES) and high school academic abilities are associated with disconnection from society at ages 18, 20, and 26. However, these associations diminish over time, and by age 26 SES is a weaker predictor of disconnection than having been on a college preparatory track (e.g., taking practice college entrance examinations) or having special educational needs in high school. At the same time, high school literacy and mathematics skills and grades are unrelated to disconnection at age 26. Prior disconnection remains one of the strongest predictors of disconnection at ages 20 and 26, highlighting the problem of repeated disconnection experienced by a small group of youth and young adults (only 0.6% of our full sample, or 11.1% of high school leavers). Finally, the odds of dropping out of the labor force--not seeking employment--are most strongly explained by gender and having dependent children, and to a lesser extent by race and high school region and urbanicity. Recommendations for supporting those most at risk of disconnection are discussed in relation to the findings. In this study, the authors used nationally representative data from a longitudinal study of U.S. young adults (from their sophomore year of high school in 2002 through approximately age 26) to explore reasons that young adults become disconnected from society. Whereas most studies of disconnected youth used data from individuals aged 16-24 at a particular point in time, the authors used longitudinal data to track changes in education, employment, and disconnection status over time and to clarify how disconnection rates vary at approximately ages 18, 20, and 26. In an attempt to clarify the relative importance of factors associated with disconnection, they conducted analyses of data from the Education Longitudinal Study of 2002 (ELS:2002; https://nces.ed.gov/surveys/els2002/). The ELS:2002 follows a cohort of millennials who were high school sophomores (10th graders) in 2002, providing data on their demographic background and their educational and employment activities at the end of high school, at approximately age 18; 2 years later, at approximately age 20; and 6 years later, at approximately age 26. This study can serve as a foundation for future efforts to identify solutions to the problem of youth disconnection.