Many recent corporate scandals have been described as resulting from a slippery slope in which a series of small infractions gradually increased over time (e.g., McLean & Elkind, 2003). However, behavioral ethics research has rarely considered how unethical behavior evolves over time and to date has not empirically examined whether individuals engage in a slippery slope of increasing unethical behavior. In this paper, we seek to extend Bandura’s (1991, 1999) social cognitive theory by demonstrating how the mechanisms of depleted self-regulation and increased moral disengagement can lead to greater unethicality over a series of gradually increasing indiscretions. Across three multi-round studies using different measures of unethical behavior, we find evidence of a slippery slope effect in which gradual, rather than abrupt, changes facilitate unethicality. Additionally, in Studies 2 and 3, this effect is sequentially mediated by depleted self-regulation and increased moral disengagement.