Unethical behavior in the workplace is a widespread phenomenon. In this article a model for the ethical culture of organizations that consists of eight dimensions is employed to explain unethical behavior. The sample was composed of 341 triads consisting of a manager and two direct reports. The results show that six dimensions of ethical culture were negatively related to observed unethical behavior: ethical role modeling of management, ethical role modeling of supervisors, capability to behave ethically, commitment to behave ethically, openness to discuss ethical issues, and reinforcement of ethical behavior. Two of the eight dimensions, clarity of ethical standards and visibility of (un)ethical behavior, were not significantly related to unethical behavior. This study demonstrates that multiple dimensions of ethical culture have to be taken into account to reduce unethical behavior. The study opens up avenues for future research about the significance of each dimension in specific settings, the dynamic relationship between these dimensions, and the instruments required to improve each dimension of ethical culture.