The purpose of this study -was to investigate the involvement of teachers in decision making process in selected secondary schools of East Wollega Zone. To conduct this study a descriptive survey method was employed. The design of the study was descriptive survey which utilizes both quantitative and qualitative approach. The quantitative data was collected first followed by qualitative data collection. Two sources of data (Primary and secondary) were employed. A total of 100 respondents (70 teachers, 6 vice principals, 21 PTAs and 3 principals) were included in the study. The schools were selected by accessibility sampling technique. Vice principals, PTAs and principals were selected using census sampling techniques. The teachers respondents were selected by system attics random sampling method. The data were gathered through questionnaire, interview and document analysis. The collected data were analyzed using frequency, percentage mean and standard deviation. The result of the study revealed that the involvement of teachers in school Planning, budgeting and income generation and school building effort found to be low. However, teachers involvement in implementing school curriculum, instruction and decision concerning students affairs and discipline found to be relatively high. But, teachers involvement in policy, rules and regulation was on medium range. In general the final, analysis of the result reflect that, the extent of Teacherâ€™s involvement in school decision making relatively low in the sample schools. Teachers involvement in school decision making depends largely on principals ability and interest to divide and delegate tasks to teachers and in general involve them in all areas of decision that affect them.