The effects of a three-year Organization Development (OD) intervention on power equalization were examined in seven experimental and seven control schools. The principals and teachers from experimental schools participated in OD workshops, in a project-coordinating council for planning and policy, and in school goal-setting activities. The power of the principals and teachers became more equalized in experimental schools than in control schools. Teacher participation in decision-making was positively related to power equalization; teacher satisfaction with the administration was partially related to power equalization. Principals in schools where power equalization occurred tended to lose power during the intervention. By the end of the intervention, newcomers were comparable to experienced teachers in power. The results support the view that OD can help reduce power differences in schools. (Author)