This meta-analysis reviewed 126 published empirical articles over the past 50 years, examining the association between marital relationship quality and physical health in over 72,000 individuals. Health outcomes included clinical endpoints (objective assessments of function, disease severity, and mortality; subjective health assessments) and surrogate endpoints (biological markers that substitute for clinical endpoints, such as blood pressure). Biological mediators included cardiovascular reactivity and hypothalamic-pituitary-adrenal axis activity. Greater marital quality was related to better health, with mean effect sizes from r = .07 to .21, including lower risk of mortality, r = .11, and lower cardiovascular reactivity during marital conflict, r = -.13, but not daily cortisol slopes or cortisol reactivity during conflict. The small effect sizes were similar in magnitude to previously found associations between health behaviors (e.g., diet) and health outcomes. Effect sizes for a small subset of clinical outcomes were susceptible to publication bias. In some studies, effect sizes remained significant after accounting for confounds such as age and socioeconomic status. Studies with a higher proportion of women in the sample demonstrated larger effect sizes, but we found little evidence for gender differences in studies that explicitly tested gender moderation, with the exception of surrogate endpoint studies. Our conclusions are limited by small numbers of studies for specific health outcomes, unexplained heterogeneity, and designs that limit causal inferences. These findings highlight the need to explicitly test affective, health behavior, and biological mechanisms in future research, and focus on moderating factors that may alter the relationship between marital quality and health. The link between "better" or "worse" marriages and "sickness and health" has been a subject of much empirical interest over the last half-century. The impact of having a better or worse marriage – marital quality – on physical well-being has remained a topic of consistent interest among scholars, practitioners, and the public. Marital quality is defined as a global evaluation of the marriage along several dimensions, including positive and negative aspects of marriage, attitudes, and reports of behaviors and interaction patterns. High marital quality is typically operationally defined by high self-reported satisfaction with the relationship, predominantly positive attitudes towards one's partner, and low levels of hostile and negative behavior. Low marital quality is characterized by low satisfaction, predominantly negative attitudes towards one's partner, and high levels of hostile and negative behavior. The connection between marital quality and health is part of a larger body of research that has consistently demonstrated robust links between social relationships and physical health. Two main types of models have been proposed to explain how social support influences physical health. In main-effect models, high levels of social integration are health promoting, regardless of whether or not one is under stress. In the stress-buffering model, the negative effects of stress occurring outside of one’s social relationships are diminished by the presence of strong social support. Close personal relationships such as marriage should be a key role sourceThis meta-analysis reviewed 126 published empirical articles over the past 50 years, examining the association between marital relationship quality and physical health in over 72,000 individuals. Health outcomes included clinical endpoints (objective assessments of function, disease severity, and mortality; subjective health assessments) and surrogate endpoints (biological markers that substitute for clinical endpoints, such as blood pressure). Biological mediators included cardiovascular reactivity and hypothalamic-pituitary-adrenal axis activity. Greater marital quality was related to better health, with mean effect sizes from r = .07 to .21, including lower risk of mortality, r = .11, and lower cardiovascular reactivity during marital conflict, r = -.13, but not daily cortisol slopes or cortisol reactivity during conflict. The small effect sizes were similar in magnitude to previously found associations between health behaviors (e.g., diet) and health outcomes. Effect sizes for a small subset of clinical outcomes were susceptible to publication bias. In some studies, effect sizes remained significant after accounting for confounds such as age and socioeconomic status. Studies with a higher proportion of women in the sample demonstrated larger effect sizes, but we found little evidence for gender differences in studies that explicitly tested gender moderation, with the exception of surrogate endpoint studies. Our conclusions are limited by small numbers of studies for specific health outcomes, unexplained heterogeneity, and designs that limit causal inferences. These findings highlight the need to explicitly test affective, health behavior, and biological mechanisms in future research, and focus on moderating factors that may alter the relationship between marital quality and health. The link between "better" or "worse" marriages and "sickness and health" has been a subject of much empirical interest over the last half-century. The impact of having a better or worse marriage – marital quality – on physical well-being has remained a topic of consistent interest among scholars, practitioners, and the public. Marital quality is defined as a global evaluation of the marriage along several dimensions, including positive and negative aspects of marriage, attitudes, and reports of behaviors and interaction patterns. High marital quality is typically operationally defined by high self-reported satisfaction with the relationship, predominantly positive attitudes towards one's partner, and low levels of hostile and negative behavior. Low marital quality is characterized by low satisfaction, predominantly negative attitudes towards one's partner, and high levels of hostile and negative behavior. The connection between marital quality and health is part of a larger body of research that has consistently demonstrated robust links between social relationships and physical health. Two main types of models have been proposed to explain how social support influences physical health. In main-effect models, high levels of social integration are health promoting, regardless of whether or not one is under stress. In the stress-buffering model, the negative effects of stress occurring outside of one’s social relationships are diminished by the presence of strong social support. Close personal relationships such as marriage should be a key role source