Over the last three decades there has been a rise in the number of workers employed during nonstandard (evening and overnight) hours; accompanying this trend has been a renewed interest in documenting workers, their families, and outcomes associated with nonstandard-hour employment. However, there are important gaps in the current literature. Few have considered how parents who work nonstandard hours care for their children when parental care is unavailable; little is known about who participates in nonparental child care during nonstandard hours, or the characteristics of those who participate. Most pressingly from a policy perspective, it is unclear how participation in nonparental child care during nonstandard hours influences child well-being. This study aims to fill these gaps. This dissertation paints a descriptive portrait of children and parents who use nonstandard child care, explores the relationship between nonstandard hours of nonparental child care participation and various measures of child well-being, and identifies longitudinal patterns of participation in nonstandard-hour child care. I find that children who participate in nonstandard-hours of nonparental child care look significantly different from those who do not participate. In particular, children are more likely to be older, identify as black or Hispanic, and reside with younger, unmarried parents who have lower levels of education. Estimates also suggest a negative relationship between participation in nonstandard-hour child care and child well-being. Specifically, children who participate in nonstandard-hour care show decreased school engagement and school readiness, increased behavioral problems, decreased social competency, and lower levels of physical health. These findings have serious implications for social and education policy.