The construct of age occupies a curious position in mainstream sociology: It is omnipresent but theoretically underdeveloped. The most prevalent approaches—age as control variable and age as life course—elide the aspect of age most relevant to the discipline, namely its operation as a system of inequality. Building on the foundation laid by scholars of life course sociology, age studies, and gerontology, I propose a new framework for thinking about age. The framework integrates insights from these fields and identifies inequality as a key axis on which several dimensions of age turn, thus placing age squarely in the domain of sociological research centering on inequalities. The article concludes with a discussion of how this framework can enhance the empirical and theoretical contributions of age-focused research. In particular, research that delves into how institutions, performances, and identities reproduce age inequality flows from this framework and constitutes a valuable contribution in its own right. Moreover, such an orientation positions the sociology of age as integral to the discipline, given its commitment to understanding how inequalities infuse social life. Expected final online publication date for the Annual Review of Sociology, Volume 48 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.