This research aims to analyze the determinants of social capital and its impacts on suicide rates by gender. The cross-sectional data from the Current Population Survey is used for social capital variables. I generate indexes corresponding to community involvement and networks of neighbors based on survey questionnaires. I use Pearson's chi-squared tests and multivariate logistic regressions to analyze social capital determinants. Regarding the impacts of social capital on suicide rates, I aggregate social capital indexes by state and county and conduct the panel data regression analysis. I find that age, education, income, unemployment, and having children are positive predictors of social capital, while divorce and metropolitan status are negative predictors. In terms of social capital’s impacts, substantial involvement in community is associated with lower female suicide rates. I argue that participation in community activities reduces social isolation and decreases suicidal behaviors. On the other hand, a strong network of neighbors is associated with higher female suicide rates, which suggests that exclusive relationships with close neighbors may impede broader social connectivity.