Income inequality has been shown to have a detrimental impact on a wide range of psychological, economic, and social outcomes. In this study, we focus on the role of income inequality in reducing civic honesty. Study 1 reanalyzed data of a “lost wallet” experiment conducted by Cohn, Maréchal, Tannenbaum, and Zuünd (2019) in 355 cities spread across 40 countries. Multilevel analyses indicated that citizens in countries with higher income inequality were less likely to return a lost wallet. Study 2 examined the causal effects of income inequality by utilizing an experimental design. We found that income inequality reduced one’s personal desire to return a lost wallet. Convergent findings from two studies indicate the crucial role played by income inequality in reducing civic honesty.