Purpose of the Study: We aimed to investigate whether social capital (obtaining support through indirect ties such as from neighbors) and social cohesion (interdependencies among neighbors) within neighborhoods positively affect the well being of older adults. Design and Methods: This cross-sectional study included 945 of 1,440 (66% response rate) independently living older adults (aged [greater than or equal] 70 years) in Rotterdam. We fitted a hierarchical random effects model to account for the hierarchical structure of the study design: 945 older adults (Level 1) nested in 72 neighborhoods (Level 2). Results: Univariate analyses showed that being born in the Netherlands, house ownership, education, income, social capital of individuals, neighborhood security, neighborhood services, neighborhood social capital, and neighborhood social cohesion were significantly related to the well being of older adults. Multilevel analyses showed that social capital of individuals, neighborhood services, neighborhood social capital, and neighborhood social cohesion predicted the well being of older adults. Single and poor older adults reported lower well being than did better off and married older adults. However, the effects of marital status and income were mediated by neighborhood services, social capital, and social cohesion. Neighborhood services, social capital, and social cohesion may act as buffer against the adverse effects of being single and poor on the well being of older adults. Implications: The results of this study support the importance of social capital of individuals, as well as social capital within the neighborhood and social cohesion within the neighborhood for well being of older adults. The well being of older adults may also be enhanced through the improvement of quality of neighborhood services. (Contains 4 tables.)