The main objective of this study was to investigate the relationship between Distributed Leadership and Organizational Effectiveness of high schools in Hamadan city. The research method was descriptive-correlation. The statistical population included all high school teachers of Hamadan in the academic year of 2015. Based on classical random sampling, using Krejcie and Morgan chart, 335 teachers were chosen. Two questionnaires were used for data collection, Distributed Leadership Questionnaire and Organizational Effectiveness Questionnaire. The reliability of the questionnaires was calculated by Cronbach’s Alph Coefficient which was acceptable (%91 and %99). Data were analyzed by descriptive statistics, and inferential statistics such as Pearson correlation coefficient, t-test for the independent groups, ANOVA and stepwise regression. Regression Analysis indicated the following results. The status quo Distributed Leadership Style and Organizational Effectiveness were above average. There were significant positive correlations between Distributed Leadership Style and Organizational Effectiveness advantage. Moreover, professional development component had greatest impact on Organizational Effectiveness.