Children may not yet understand political issues or be engaged in politics, but identification with social groups emerges early; indeed, nearly a third of first-graders report identification with a political party. As a result, it is likely that ingroup favoritism (or preference for members of one's own political group) and outgroup derogation (or animus toward members of other political groups) appear sooner than previously assumed. In this article, the author reports on a study that examined whether these attitudes appear as early as pre-adolescence, and if so, how youth affective polarization levels compare to adult levels.