This study aims to know the implementation of authentic assessment done by science teachers at Public Junior High School/ Public Islamic Junior High School in Banda Aceh area. This study uses a quantitative approach with descriptive methods. Data collection technique is done by using questionnaires where researcher distributes the questionnaires to science teachers and interviews some of them. The source data of this research are 20 science teachers in Public Junior High School/Public Islamic Junior High School Banda Aceh. The chosen schools are Public Junior High School number 1, 2, and 18 Banda Aceh. The results of this study is that not all of the teachers face difficulties in implementing authentic assessment in school due to most of the teachers (68%) at Public/Public Islamic Junior High School Banda Aceh have implemented the authentic assessment in each school. At the stage of readiness of authentic assessment, the majority of teachers (73.5%) have already implemented it well; the teachers can gather information of learners, can choose various teaching techniques, and conduct daily, midterm and final tests. In assessment planning (56.6%), it is still found that teaching planning which does not have clear assessments, such as questions instrument gratings, questions instrument, and scoring guidelines. While in implementing the authentic assessment, the majority of the teachers (74.5%) do assessment when teaching learning process goes