Powerful individuals have been known to be less ethical than powerless individuals. In real life, power is unstable, and multiple social interactions may cause loss of power. However, prior research has assumed the power structure to be stable and thus overlooked the potential interaction of power and stability in affecting ethical behavior. Using the approach-inhibition theory of power, we predicted that stability of power moderates power’s effect on unethical behavior. Results from an experimental study revealed that a difference between powerful and powerless individuals’ unethical behavior was observed only in the stable-power condition, but not in the unstable-power condition. Our results highlight that the link between power and unethicality is broken when power is unstable: Powerful individuals are no more unethical than powerless individuals when they face a greater possibility of losing their power.