The glass ceiling refers to the difficulty of women trying to be promoted into the top management levels. The present study examined managers' potential explanations, implicit or explicit, for why women rarely reach the top hierarchical levels in their own organization. Among 685 managers at a large Midwestern insurance company, a model was supported in which beliefs about interpersonal and situational variables in the organization were related to the perception that men and women were treated differently overall, which, in turn, was related to the belief that a glass ceiling existed. The model was not different for male and female managers, but women tended to perceive that each element of the model existed to a greater extent than men did.