Although much research has been conducted on the predictors and outcomes of both subjective well-being (SWB) and psychological well-being (PWB), the magnitude and direction of the causal relationship between these constructs remain unclear. The studies reported in this article were designed to assess the temporal relationship between SWB and PWB during a period of 20 years. The studies used 3 waves of survey data, with intervals of 10 years, from the Midlife in the United States project, a representative longitudinal panel study of American adults (N = 2,731). Cross-lagged panel analyses were conducted to examine directionality of the relationships. Results showed that the autoregressive effects were large, suggesting a high degree of stability in SWB and PWB over time. Yet the levels of stability were generally higher for PWB than SWB. Whereas PWB unequivocally predicted increases in SWB over time, the prospective effects of SWB on PWB were inconsistent (i.e., positive, negative, or nonsignificant) across various points in time. The study findings suggest that PWB represents a more robust and consistent antecedent of future well-being than SWB. (PsycINFO Database Record (c) 2019 APA, all rights reserved).