BACKGROUND: Differences in social and environmental factors contribute to disparities in fatal injury rates. This study assessed the relationship between social vulnerability and homicide and suicide rates across United States counties. METHODS: County-level age-adjusted homicide and suicide rates for 2016-2020 were linked with data from the Centers for Disease Control and Prevention's 2020 Social Vulnerability Index (SVI), a dataset identifying socially vulnerable communities. We conducted negative binomial regressions to examine the association between SVI and homicide and suicide rates, overall and by Census region/division. We mapped county-level data for SVI and homicide and suicide rates in bivariate choropleth maps. RESULTS: Overall SVI was associated with homicide rates across U.S. counties. While no association was found for overall SVI and suicide rates, Socioeconomic Status and Racial & Ethnic Minority Status domains were associated. The geographic distribution of SVI and homicide and suicide rates varied spatially; notably, counties in the South had the greatest levels of social vulnerability and greatest homicide rates. CONCLUSIONS: Our findings demonstrate county-level social vulnerability is associated with homicide rates but may be more nuanced for suicide rates. A modified SVI for injury should include additional social and structural determinants and exclude variables not applicable to injuries. PRACTICAL APPLICATIONS: This study combines the SVI with homicide and suicide data, enabling researchers to examine related social and environmental factors. Modifying the SVI to include relevant predictors could improve injury prevention strategies by prioritizing efforts in areas with high social vulnerability.