Assessment has the important role in education field. There is formative assessment that is often used by almost all teachers or lecturers. Formative assessment is conducted on going learning process and used to provide feedback to the students to serve as a basis for improving the learning process. According to researcher experience or observation there are many students can improve their learning by doing formative assessment. Therefore this study is conducted to obtain the students’ perception on the implementation of formative assessment at English Language Education Department of a private university in Yogyakarta. There are four students of English Language Education Department of a private university in Yogyakarta batch 2014 who become the participants. In addition, individual interview as the data collection method direct the researcher to find out various opinions of students’ perception of formative assessment. The first findings of the study reveals that there are several kinds of formative assessment implemented at a private university in Yogyakarta such as, essay, role-play, vocabulary quiz, group discussion, oral presentation, and debate. The second findings, there are several benefits of formative assessment that students get including to inform students’ weaknesses, to improve students’ knowledge, to enrich the vocabularies, to improve speaking skill, and to motivate the students to learn. The third findings, this study found about the negative impacts that students’ get from formative assessment are time consuming, getting bored, and under-pressured. The findings of this study will become important findings related to students’ perception about formative assessment.