Does power trigger hubris? We consider the effects of having power and the role of dispositions of power-holders on hubris and self-serving behaviour. Drawing on field and experimental research, we demonstrate that having power biases people’s self-concept in a hubristic manner. Power elevates confidence in oneself, one’s perceived competence and heightens self-esteem. Consequently, people in power communicate in a decisive and assertive manner, and so they are influential and have advantages in negotiations. Many feel entitled, take less advice from others, and neglect others’ perspectives. Crucially, the ways power affects people depends on power-holders’ dispositions and goals. People with dominant and hubristic inclinations are more likely to strive for, and reach positions of power. Such self-selection processes enable bad apples to emerge at the top, exuberating the dark side of hubristic behaviour often seen in the high echelons.