Precarious employment (PE), which encompasses the power relations between workers and employers, is a well-established social determinant of health that has strong ramifications for health and health inequity. In this review, we discuss advances in the measurement of this multidimensional construct and provide recommendations for overcoming continued measurement challenges. We then evaluate recent evidence of the negative health impacts of PE, with a focus on the burgeoning studies from North America and South America. We also establish the role of PE in maintaining and perpetuating health inequities and review potential policy solutions to help alleviate its health burden. Last, we discuss future research directions with a call for a better understanding of the heterogeneity within PE and for research that focuses both on upstream drivers that shape PE and its impacts on health, as well as on the mechanisms by which PE causes poor health. Expected final online publication date for the Annual Review of Public Health, Volume 45 is April 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.