This paper aims to describe the implementation of curriculum 2013 assessment on students’ writing skill at senior high school and the teacher’s difficulties in implementing the curriculum for assessing their students’ writing skills. A qualitative method was used in this study by using the research approaches of classroom observations, semi-structured interviews, and documentations. The study was conducted in SMAN 2 Langsa, Aceh. The participants of this study were two English teachers at the school. The findings of the study showed that the teacher had implemented the curriculum 2013 assessment on students’ writing skill as in line with the framework contained in the curriculum. Further, individual students’ factors, complex assessment, and limited teaching-learning time were considered as difficulties by the teachers in implementing the curriculum 2013 assessment.