In low-fertility contexts, how many children people have is largely a product of how many children they want. However, the social, institutional, and individual factors that influence how many children people want are not well understood. In particular, there is scant evidence about how fertility expectations change over the life course. This article provides an empirical description of changes in women’s expected fertility over the entire span of childbearing years. Using data from the National Longitudinal Survey of Youth, 1979 cohort, group-based trajectory analysis illuminates common patterns in the evolution of fertility intentions and identifies individual characteristics associated with these patterns. Factors related to family formation, such as marriage and whether a woman has a child at an early age, are found to be the most consistent correlates of patterns of change in expected family size.