29% of employees report having had an idea stolen by a colleague, at least once (Forbes, 2016). Despite the prevalence of idea theft throughout creative work, there is a paucity of scholarship on this phenomenon. As such, in this dissertation, I study the consequences of idea theft. I begin this work by first defining idea theft and illustrating the different forms it has taken in prior research. Next, across six empirical studies, I investigate the relative interpersonal consequences for stealing ideas compared to money. In these studies, I show that individuals who steal ideas are judged to have worse character than those who steal money (i.e., Study 1). Studies 2a and 2b show this is because people form stronger internal attributions in the case of idea theft than money theft. Studies 4 and 5 address a compelling alternative explanation for these effects—that idea theft is judged more harshly because ideas are thought to be of more value than money. I test this alternative hypothesis by first measuring the subjective value of the stolen idea and stolen money (Study 4); second, I hold the value of the stolen idea and money fixed at $1,000 (Study 5). The results of these studies provide no support for this alternative explanation. Next, I demonstrate the interpersonal consequences for stealing ideas in terms of coworker support (Study 3) and coworker selection (Study 6). Finally, I explore two boundaries of the consequences of idea theft—the creativity of the stolen idea (Study 7) and organizational culture (Studies 8-10). In Study 7, I show that individuals judge a thief who has stolen a creative idea more harshly than one who has stolen a practical idea. In Studies 8-10, I demonstrate that priming collectivistic cultural values results in more lenient judgments and punishment for idea theft. I argue this is due to collectivistic organizational cultures drive weaker theories of idea ownership—I find support for this hypothesis in Study 9. Finally, in Study 10, I find that weaker theories of ownership also increase individuals’ willingness to emulate idea theft behaviors. Taken together, the body of this works posits that idea theft is an understudied and consequential phenomenon with significant implications for knowledge work.