The chapter discusses the relationship between subjective well-being, health, and aging. Subjective well-being encompasses three aspects: evaluative well-being (life satisfaction), hedonic well-being (emotional states), and eudemonic well-being (sense of purpose and meaning). Recent studies have shown that in high-income, English-speaking countries, life satisfaction peaks in middle age and declines in old age, forming a U-shaped pattern. However, this pattern is not universal, with different regions showing varying trends. For example, in the former Soviet Union and eastern Europe, life satisfaction decreases with age, while in Latin America and sub-Saharan Africa, it remains stable. The relationship between physical health and subjective well-being is bidirectional, with poor health leading to reduced well-being and high well-being potentially protecting against health issues. Longitudinal studies, such as the English Longitudinal Study of Ageing, have found that eudemonic well-being is associated with increased survival rates. The authors conclude that subjective well-being is an important factor for both economic and health policies, but current theories do not fully explain the variations in well-being across different regions. They also highlight the need for further research to understand the underlying processes and the implications for policy.The chapter discusses the relationship between subjective well-being, health, and aging. Subjective well-being encompasses three aspects: evaluative well-being (life satisfaction), hedonic well-being (emotional states), and eudemonic well-being (sense of purpose and meaning). Recent studies have shown that in high-income, English-speaking countries, life satisfaction peaks in middle age and declines in old age, forming a U-shaped pattern. However, this pattern is not universal, with different regions showing varying trends. For example, in the former Soviet Union and eastern Europe, life satisfaction decreases with age, while in Latin America and sub-Saharan Africa, it remains stable. The relationship between physical health and subjective well-being is bidirectional, with poor health leading to reduced well-being and high well-being potentially protecting against health issues. Longitudinal studies, such as the English Longitudinal Study of Ageing, have found that eudemonic well-being is associated with increased survival rates. The authors conclude that subjective well-being is an important factor for both economic and health policies, but current theories do not fully explain the variations in well-being across different regions. They also highlight the need for further research to understand the underlying processes and the implications for policy.