The first epidemiologic study was conducted to prospectively examine the association between Food Environment Index (FEI) and gastric cancer (GC) risk in the US. Surveillance, Epidemiology, and End Results provided information on GC incident cases diagnosed between 2000 and 2015 from 16 population-based cancer registries across the US. The county-level food environment was assessed using the FEI, an indicator of access to healthy foods (0 is worst, 10 is best). Poisson regression was used to calculate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for the association between FEI and GC risk adjusting for individual-level and county-level covariates. Higher levels of FEI were associated with a statistically significant reduced risk for GC (n = 87,288 cases; adjusted IRR for every score increase = 0.50, 95% CI 0.35, 0.70; P < 0.001; adjusted IRR for the medium vs. low category = 0.87, 95% CI 0.81, 0.94; and adjusted IRR for the high vs. low category = 0.89, 95% CI 0.82, 0.95). These results suggest that a healthy food environment, as measured by FEI, may be a protective factor for GC in the US. To reduce the GC incidence, further strategies to improve food environment at the county level are warranted.