This study explored the relationship between state income inequality and individual tooth loss among 386,629 adults in the United States who participated in the 2008 Behavioral and Risk Factor Surveillance System. Multilevel models were used to test the association of the state Gini coefficient with tooth loss after sequential adjustment for state- (median household income) and individual-level confounders (sex, age, race, education, and household income), as well as state- (percent receiving fluoridated water and dentist-to-population ratio) and individual-level mediators (marital status and last dental visit). The state Gini coefficient was significantly associated with tooth loss even after adjustment for state- and individual-level confounders and potential mediators (Odds Ratio, 1.17; 95% Confidence Interval, 1.05 to 1.30). This study provides support for the relationship between state income inequality and individual tooth loss in the United States.