The study investigated the effect of European Language Portfolio (ELP) on students' attitudes towards learning English. The study also examined the attitudes of students and teachers towards the ELP and its implementation into the curriculum. The study was conducted at Bülent Ecevit University the School of Foreign Languages Basic English Department in the 2016-2017 academic year. The data collection instrument employed in this study was semi-structured interviews which were conducted with thirty students and five teachers. The analysis of the interviews indicated that the ELP can promote self-assessment on the condition that it is used effectively both by the teachers and students and as a consequence the students support having more positive attitudes towards learning English. Additionally, it was found that the students felt positive towards the ELP and working with it as far as they used it correctly in their classes as part of the curriculum. In addition, the findings of the study indicated that both the teachers and the students believed that the ELP was a tool for self-assessment; however, the implementation of the ELP in the curriculum of the School of Foreign Languages at Bülent Ecevit University needs support since the ELP has only been newly introduced in Turkey as well and the teachers have very little information about the use and effectiveness of the ELP in language learning. However, this study showed that the ELP could be used as a tool to promote self-assessment and to create learner-centered classrooms in Turkey.