The purpose of this study was to assess EFL teachers’ perceptions and practices of formative language assessment in teaching writing in some selected primary schools in South Mecha district. Descriptive research design was employed to address the problem. The participants of the study were 20 teachers who were selected using comprehensive sampling technique from five primary schools in South Mecha district. To gather pertinent data, questionnaire (open-ended and close-ended), classroom observation and document analysis were employed. The close- ended questionnaire and classroom observation data were analyzed using both descriptive and inferential statistics. The data gathered through open- ended questionnaire as well as document analysis was analyzed qualitatively and thematically. The findings indicated that the grade seven and eight EFL teachers practiced the FLA at a medium level though they have a positive perception regarding the significance of FLA for the development of students’ writing skills. In addition to this, the inferential statistical data demonstrated that there is a positive, strong and significant correlation between teachers’ perception and their practice of FLA (r= .512*, P value is .021 less than 0.05). However, the triangulation made with qualitative data about EFL teachers’ perception of FLA and their actual practices were not consistent. Although there are various FLA techniques in assessing the students’ skills, a few of them: group work, homework, classwork and tests/quizzes were frequently employed in the instruction. From all sources, it can be concluded that teachers employed a few FLA techniques. As a result, it was recommended that teachers have a responsibility to practice different FLA techniques while teaching writing and the responsible body should support, assess and fulfill necessary teaching/ learning materials to practice the FLA in the instruction.