(ProQuest: ... denotes formulae omitted.)Family-related attitudes are key correlates of various family processes and outcomes, including family formation and dissolution, the division of household labor, and childbearing and parenting. Despite the important theoretical and policy implications associated with the formation of these attitudes there is little systematic knowledge about it. Furthermore, researchers often argue that these attitudes determine behaviors, not vice versa. In particular, how family attitudes change as one gets older is seldom examined,althoughpastresearchhaspaidextensive attention to the liberalizing trend in family attitudes across cohorts. This lack of understanding is in part due to a lack of longitudinal data at the individual level. In fact, little is known about the within-person changes in family attitudes over time. The available longitudinal evidence comes predominantly from the United States, and no studies from Asia have been conducted.Family formation and dissolution, childbirth, the transition from school to work, unemployment, and retirement are important life stage transitions that most people experience during their lifetime. These transitions may change what people experience, how they define themselves, and with whom they interact, thereby influencing their attitudes. A few studies, mostly conducted in the West, suggest that some of these life stage transitions indeed affect family-related attitudes (e.g., Baxter, Buchler, Perales, & Western, 2015; Fan & Marini, 2000; Trent & South, 1992), and more research, especially in the Asian context, is needed.We filled these gaps in the literature by analyzing the attitudes toward family formation of women in their 20s and 30s in South Korea (hereafter Korea). Data came from the Korean Longitudinal Survey of Women and Families (KLoWF; http://klowf.kwdi.re.kr/main.do? sLang=EN), a nationally representative longitudinal survey conducted in 2007, 2008, 2010, and 2012. We constructed a multiple-item scale that summarizes family-formation attitudes- namely, whether and when respondents think women should marry and have a child.In this study, using cross-sectional ordinary least squares (OLS) regression, we analyzed how women's attitudes relate to their ages. This analysis, in which age and cohort effects are indistinguishable, served as a preliminary examination of age patterns in family attitudes. Second, with individual fixed effects (FE) regression, we investigated changes in attitudes over time. Last, using life stage transitions as covariates in the cross-sectional and FE regression analyses, we examined the extent to which the transitions explain the age gradient in attitudes across individuals and the within-individual changes over time.The cross-sectional results show that older women tended to hold more traditional attitudes than their younger counterparts. Over the 4-year period between 2008 and 2012, women's attitudes became more, not less, traditional. Marriage and childbearing affected both the cross-individual differences and the within-individual changes in attitudes, while no evidence was found for the effects of educational attainment, work, and living arrangements with parents. We explain these findings within the context of a remarkable delay and decline in marriage and fertility in Korea and draw implications for other societies where strong family-centered and gender-divided cultures lag behind rapid economic and social changes.PAST LITERATURE AND THE CURRENT STUDYDifferences and Changes in AttitudesAttitudes toward family-related issues such as marriage, divorce, childbearing, and gender roles are related to family-related behaviors and decision making. The previous theoretical literature has tended to consider family-related attitudes as explanatory factors for family outcomes: These attitudes are the lenses through which individuals interpret the symbolic meaning of their actions and relationships with other people, and, hence, the attitudes affect people's intentions and decisions regarding fertility and marriage (Balbo, Billari, & Mills, 2013; Davis & Greenstein, 2009; Willoughby, Hall, & Luczak, 2015). …