Rizki Febri Andika Hudori. S891402047. 2015. The Enactment of Portfolio Assessmentin English Writing Classes (A case study at a Junior High School in 2015). Guided by thefirst consultant: Prof. Dr. Joko Nurkamto, M.Pd., and the second consultant: Dr. Suparno,M.Pd. Thesis. Surakarta. English Education Department of Graduate Program, TeacherTraining and Education Faculty, Sebelas Maret University.The objectives of this research were to (1) identify the teacher’s perspective about thecharacteristics and practices of portfolio assessment in English writing classes, (2)investigate the enactment of portfolio assessment in English writing classes, and (3)investigate the extent to which the enactment of portfolio assessment affected the qualityof teaching learning process in English writing classes. Design of this research was casestudy. This research was conducted at a junior high school in Jember in 2015. Techniquesof collecting data used were observation, interview, and document analysis. In analyzingdata, Miles and Huberman’s model was considered to be used through data reduction,data display, and conclusion. Based on the research data, it was found that (1) TheEnglish teachers assume that assessing writing by using portfolio assessment is good anduseful, (2) portfolio assessment is enacted in English writing classes based on someparameters such as documenting the students’ writings, scoring by using clear scoringrubric, giving feedback and encouraging students’ self-reflection, giving chance tostudents to revise, and keeping the portfolio document as the document model, and (3) itgives good effect to the quality of teaching learning process in English writing classes.From those research data, it can be concluded the English teachers have goodunderstanding about the characteristic and practices of enacting portfolio assessment inEnglish writing classes, and product portfolio is chosen as the type of portfolio.Moreover, portfolio assessment brings some benefits which can be addressed to bothstudents and English teachers