In this research, we explore how coworker ideation levels or, more specifically, the average ideation levels of coworkers within a workgroup affect a focal employee's ideation. We examine an underlying mechanism and a boundary condition of this influence process. Drawing on social cognitive theory, we argue that high coworker ideation levels are likely to stimulate a focal employee's ideation by enhancing their creative self-efficacy. Furthermore, we suggest that this positive influence is likely to be strengthened when the focal employee has a higher than lower quality of exchange with their coworkers. The results of two field studies provide support for all of the hypotheses. Contributions to theory and insights into practice and future research are discussed.