Prompted by increased concern about teacher turnover, the study wasrnconducted to establish the magnitude and identify the causes of the problem inrnOromia Government Secondary Schools (OGSS) using data obtained from 365rn(172 former (FOGSSTs) and 193 current (COGSSTs)) respondents in 30rncomplete secondary schools of six Oromia Zones. The study focuses on sevenrnplausible causes of turnover: salary and opportunities, administration andrnsupervision, performance evaluation, teaching related factors, availability ofrnbetter employment opportunities, students' character and environmentalrnfactors.rnThe data analysis was made using percentage of frequency, median, weightedrnmean, standard deviation and ranking methods. Differences between differentrngroups in terms of gender, length of service years, age, as well as betweenrnFOGSSTs and COGSSTs were also explored using Mann Whitney U Test.rnThe results identified that turnover of teachers is a function of economic andrnmanagerial factors, whereas environmental factors and students' character arernthe least reasons for the problem. In relation to the groups, female, lessrnexperienced, younger and dissatisfied teachers tend to leave the schools atrnhigher rate than their counterparts. Therefore, the prescriptions for the curernalso lie in bringing about improvement in these factors