Neighborhood social cohesion (NSC) refers to a sense of belonging, shared values, and trust among neighbors. This study investigated NSC as a protective factor on residents' self-rated health (SRH), well being (WB), and psychological distress (PD), and whether NSC plays a role in understanding how neighborhood socio-demographic contexts influence the health and well being of residents. These research questions were investigated among a representative sample of residents greater metropolitan Phoenix, a region encompassing great diversity across its neighborhoods in their economic, social and cultural makeup. The Arizona Health Survey (AHS) and the 2000 Census provided measures at individual and neighborhood levels, respectively. Three neighborhood contextual variables were investigated - neighborhood average education level, median household income, and ethnic composition. Results supported the protective effects of NSC on each health outcome, and further supported the role of NSC as a mediating mechanism of the effects of neighborhood contexts on the physical and emotional health of residents. Additional exploratory analyses were conducted to further examine the effects of neighborhood ethnic composition on NSC. Implications and future lines of inquiry are discussed. The concept of social cohesion has the potential to capture how social resources, generated through mutual ties among residents, contribute to the health and well being of diverse communities.