Yan, XuParenthood in general, and motherhood in particular, has long been documented to bring both costs and benefits to adults’ well-being. The well-being of mothers and the impacts of motherhood on women’s well-being are also found to vary depending on the social groups women belong to. However, current findings on racial-ethnic and socioeconomic differences in mothers’ well-being are limited, inconsistent, and concentrated predominantly in Western developed countries. Poor mental health in mothers can negatively affect children’s development. Children experiencing development problems, in turn, can also trigger poor mental health in mothers. Yet, so far, we know little about whether this bi-directional relationship varies according to mothers’ socioeconomic status (SES). Using data from the Early Childhood Longitudinal Study: 2010-11 Kindergarten Class and the China Family Panel Study, this dissertation answers three sets of research questions. First, are there racial-ethnic differences in U.S. mothers’ parenting-related stress and its associations with depression? Using latent profile analysis to address the multidimensionality of mothers’ parenting stress, I find racial-ethnic disparities not only in the type of parenting stress that mothers face but also in the associations between each type of parenting stress and mothers’ depression levels. Second, do Chinese mothers aged between 20 and 49 report better or worse well-being than their peers who have never had a child? Does the effect of motherhood on women’s well-being vary by women’s SES? The results show that while Chinese mothers generally report worse well-being than women without children, the negative well-being consequences of parenting non-adult children are less pronounced among rural-to-urban migrant women with moderate income and education than among their more disadvantaged and privileged peers. But having only adult children, when compared to not having children, is more harmful to migrant women than to more privileged women. Third, how do U.S. mothers’ parenting stress and children’s developmental outcomes influence each other bi-directionally over time? How do mothers’ education levels moderate the relationships? I find negative mutual impacts between mothers’ parenting stress and children’s developmental outcomes. But both the harm of high parenting stress on child outcomes and the detrimental impact of children’s developmental problems on parenting stress are more pronounced among mothers without a college degree. Overall, my findings reveal the complex roles of race-ethnicity, SES, and national contexts in shaping mothers’ parenting experiences, well-being, and children’s developmental outcomes. I conclude by discussing the empirical, theoretical, and methodological contributions of these findings to research on social inequalities in motherhood and the consequences on mothers’ well-being and children’s outcomes. Additionally, I address the policy implications of this dissertation for enhancing the well-being of women and children with diverse social backgrounds.enDissertationSociology