This study examines the ways in which peer and self-assessment can work as a tool for developing EFL students’ language skills in the context of secondary education in Sweden. After giving a brief overview of the relevant research and terminology about those assessment methods, the authors analyse the possible benefits of peer and self-assessment in the English classrooms in Sweden. The current Swedish educational, documents strongly influenced by Vygotsky’s sociocultural approach to learning, highlight the importance of social interaction, self-awareness and learner autonomy as fundamental elements for language development. Moreover, peer and self-assessment are explicitly recommended by the school documents as important tools to promote language learning. Through a thorough analysis and discussion about relevant research on the subject and the current educational documents, this study presents peer and self-assessment as important tools to help students develop their overall language skills. With proper training, peer feedback equips students with the skills and strategies for effectively engaging in their own learning process, which is a final goal of the national curriculum and of the syllabus for English for the upper-secondary school. Peer and self-assessment are, indeed, important complements to teacher feedback in the EFL Swedish classrooms. However, in order to be able to help their students, teachers themselves need to understand the value of such methods, and to be trained in how to effectively implement them. Therefore, this study concludes that peer and self-assessment should constitute an important part of teacher education in Sweden.