This study aims at investigating practices and beliefs of teachers regarding the use of peer assessment in EFL writing in Jimma Seto Semro and Jiren preparatory and high schools in South Western Ethiopia. In this study, a descriptive survey based on both qualitative and quantitative data were used. To achieve the objective, all (13) EFL instructors in Seto Semro and Jiren high schools and participated in the study. Questionnaire consisting of closed and open-ended questions were utilized as a main data collection tool which was substantiated by an interview. The findings of the study showed that the majority of teachers are practising peer assessment in EFL writing. The findings of this study revealed that peer feedback was found to be beneficial, for it increased teachers' positive beliefs and motivation in English writing class. Participants also liked peer review and the majority liked to carry out this peer assessment. Peer evaluation was helpful for improving students' writing in lay out, content, organization, language use, spelling, capitalization, mechanics, grammar and vocabulary. Based on the findings, it was recommended that teachers of writing should use peer assessment to help students improve their writing in the areas of spelling, mechanics and grammar. It is further recommended, that there is a need to train EFL teachers to make them aware of the idea that peer assessment develops students' writing skills.