Social relationships significantly influence mental and physical health, health behaviors, and mortality risk. Sociologists have established the link between social relationships and health outcomes, identifying mechanisms such as behavioral, psychosocial, and physiological pathways. Social relationships can have both positive and negative effects on health, with benefits including reduced mortality, improved health behaviors, and enhanced mental health. However, strained or conflicted relationships can lead to poor health outcomes, including increased stress, poor health habits, and higher mortality risk. The impact of social relationships varies across the life course, with different types of relationships (e.g., family, friends, marriage) playing key roles at different stages of life. Social ties also have cumulative effects on health over time, with social isolation and strain contributing to long-term health disadvantages. Social relationships are not equally distributed across the population, with disparities in access, benefits, and costs varying by age, gender, race, and socioeconomic status. Policies should aim to promote and protect social ties, particularly for vulnerable groups, while avoiding policies that increase relationship burdens or undermine positive social connections. Social ties can influence health outcomes not only for individuals but also for their social networks, suggesting that interventions should consider the spread of health behaviors through social networks. Research highlights the importance of addressing social isolation, reducing the negative effects of strained relationships, and ensuring that policies support the health of all individuals, especially those at higher risk. Public policy should integrate scientific evidence on the link between social relationships and health to develop effective strategies that promote population health. This includes policies that support social connections, reduce social isolation, and address the health disparities associated with social inequality. Future research should explore the mechanisms through which social relationships influence health, as well as the ways in which these relationships vary across different social groups. By understanding these dynamics, policymakers can create more effective interventions that improve health outcomes for all individuals.Social relationships significantly influence mental and physical health, health behaviors, and mortality risk. Sociologists have established the link between social relationships and health outcomes, identifying mechanisms such as behavioral, psychosocial, and physiological pathways. Social relationships can have both positive and negative effects on health, with benefits including reduced mortality, improved health behaviors, and enhanced mental health. However, strained or conflicted relationships can lead to poor health outcomes, including increased stress, poor health habits, and higher mortality risk. The impact of social relationships varies across the life course, with different types of relationships (e.g., family, friends, marriage) playing key roles at different stages of life. Social ties also have cumulative effects on health over time, with social isolation and strain contributing to long-term health disadvantages. Social relationships are not equally distributed across the population, with disparities in access, benefits, and costs varying by age, gender, race, and socioeconomic status. Policies should aim to promote and protect social ties, particularly for vulnerable groups, while avoiding policies that increase relationship burdens or undermine positive social connections. Social ties can influence health outcomes not only for individuals but also for their social networks, suggesting that interventions should consider the spread of health behaviors through social networks. Research highlights the importance of addressing social isolation, reducing the negative effects of strained relationships, and ensuring that policies support the health of all individuals, especially those at higher risk. Public policy should integrate scientific evidence on the link between social relationships and health to develop effective strategies that promote population health. This includes policies that support social connections, reduce social isolation, and address the health disparities associated with social inequality. Future research should explore the mechanisms through which social relationships influence health, as well as the ways in which these relationships vary across different social groups. By understanding these dynamics, policymakers can create more effective interventions that improve health outcomes for all individuals.