Understanding and preventing unethical behavior is essential for the welfare of society. Prior research has shown that affective processes have consequential effects on such behavior. Through three different research designs, the current research aims to unravel the mixed findings relating positive affect and unethical behavior by suggesting that feeling gratitude may differentially influence one’s ethicality. The first chapter consists of a review paper proposing that feeling gratitude may differentially influence one’s ethicality through three distinct pathways: motivational (greed), cognitive (moral disengagement), and relational (felt-security). The second chapter includes two experimental studies testing some of the aforementioned propositions. Finally, in our third chapter, we investigate the effect of a gratitude expression intervention and suggest using experimental data that under certain situations (i.e., workplace ostracism), such interventions may result in undesirable outcomes. Together, our research provides clarification on the relationship between positive affect and unethical behavior, and suggest that gratitude activities do not always lead to positive consequences and that they should be used with caution.