Social, economic, political and technological trends over the past several decades have caused a number of adaptive changes in the labor market, including the fundamental transformation of the nature and organization of employment. One of the most notable changes is the decline in the number of jobs resembling the Standard Employment Relationship (SER; i.e., permanent, full-time, regularly scheduled work with secure wages and benefits). Compared to the last several generations, workers today are more likely to experience non-permanent contractual arrangements; volatile and asocial work schedules; stagnant wages and decreased access to fringe benefits; less opportunity to develop skills; and generally more imbalanced employer-worker power dynamics, including the lack of collective bargaining or other involvement in workplace decision-making. These changes are thought to have far-reaching consequences for the labor market experiences of millions of Americans, and are likely to disproportionately impact marginalized working populations. However, these employment trends have not been adequately examined from a public health perspective. This dissertation aims to improve our understanding of the linkages between employment, health and health inequities, with a specific focus on advancing both theory and methods needed to approach this topic from occupational health and social epidemiologic perspectives. First, we develop a novel conceptual model that attempts to embed the work-health relationship within a broader social context. We argue that researchers should direct more attention to the many ways in which work influences health beyond the physical and psychosocial hazards that are typically emphasized—including the quality of the employment relationship, how work structures non-work life (e.g., determining one’s non-work-life schedule), and the contribution of work to one’s overall status within a society. We then detail specific mechanisms by which workers may be differentially exposed to, or be differentially impacted by, adverse work characteristics. Next, we conduct a series of three empirical studies to advance the multidimensional construct of employment quality, which accounts for both the contractual and relational aspects of employment that effect health independently of physical and psychosocial environments. First, we used data from the U.S. General Social Survey and a latent class analysis approach to identify eight distinct forms of employment in the U.S. Consistent with theory and prior research, one employment quality (EQ) type resembled the historical conception of the SER, while other EQ types were characterized by various configurations of beneficial and unfavorable employment conditions. We also found that EQ is unequally distributed across sociodemographic groups and throughout the labor market. In the second study, we found that EQ was associated with three measures of health, including self-reported health (SRH), frequent mental health (FMD), and occupational injury. We also found support for three hypothesized mechanisms linking EQ to health, including material deprivation (e.g., inadequate income), employment-related stressors (e.g., job insecurity), and occupational risk factors (e.g., physical exposures). These mediators may represent potential avenues for interventions to improve workers’ health. In the third study, we found evidence that the unequal distribution of EQ across women and men played a significant role in observed gender inequities in SRH and FMD. In particular, our results suggest that if women had the same EQ as men, they would report significantly better health. While employment conditions have received less attention compared to other aspects of socioeconomic position, such as education and income, EQ is identified as a potentially important mechanism contributing to social gradients in population health.