Quality education is very important for social, cultural and economic development. It is a vitalrnin trument in the creation of a modern economy. However quality of education is influenced byrnthe complex ct of external and internal factors, which negatively influence instructionalrnacti it . The purpose of this study wa therefore, to examine the impact of the main in schoolrnfactors, which affect the quality of secondary education in Oromia region.rnThe sample consisted of 798 students, 283 teachers and eighteen secondary schools principalsrndrawn from eighteen sample schools as well as nine supervisors from woreda and zonerneducation offices in the three zones (East showa, East Wollega and East Hararge) of the region.rnRegarding the respondents teachers and students from each sample school and supervisors fromrnthe three zones were selected randomly. But principals from each sample schools and purposelyrnselected. In addition, observations were used to compare the response of the respondents withrnwhat is actually available in the schools. To carry out the study a descriptive survey method wasrnused. To gather the necessary data questionnaire (open-ended and close-ended), interview,rnob ervation and documents were the main instruments employed. Instruments were analyzed inrnpercentage and chi-square was used to test the degree of differences among the respondents.rnThe results obtained from the study showed that, the main in school factors that affected qualityrnof secondary education were poor ability of the students in the language of instruction,rnirrelevance and difficulty of the curriculum content, shortage of qualified teachers andrnovercrowded nature of the classrooms. In addition, in sufficiency of school facilities in thernservices they provide, shortage of textbooks and incompetence of school principals were amongrnthe factors, which contributed to the low level of quality of education. Furthermore, the mainrnreason for shortage of qualified teachers in the region was found to be high turnover. Thernfindings of the study also suggested that half of the principals in the sample schools were belowrnthe minimum required qualification set by the Ministry of Education. In addition, only one ofrnthese principals was a diploma graduate in school administration and all the remaining werernsubject area graduates.rnBased on the findings and conclusions, recommendations are made to alleviate the existingrnproblems. Accordingly encouraging private investors to open private schools encouragingrncommunity involvement in supplying school facilities, improving method of teaching English atrnprimary as well as secondary schools, encouraging students to debate on some i sues throughrnEnglish language, encouraging private investors to publi h textbooks so that book would bernavailable on sale for interested consumers, motivating teachers by providing various incentives,rnintroduction of quality assurance mechanisms to the secondary schools, and others which arernassumed to solve the identified problems were recommended