Analyses included 11,562 children ages 3–5 years living in 160 residential ZIP codes. A higher homicide rate (at the 75th vs 25th percentile) was associated with a 22% higher prevalence of obesity (95% CI for the prevalence ratio (PR): 1.05 to 1.41). A higher density of street trees (at the 75th vs 25th percentile) was associated with 12% lower prevalence of obesity (95% CI for the PR: 0.79 to 0.99). Other neighborhood characteristics did not have significant associations with childhood obesity.