This dissertation is concerned with a conceptual analysis and an empirical investigation of how self-assessment is construed by students, teachers, and institution managers in an English as a Foreign Language (EFL) setting. The conceptual analysis is made by a review of the relevant literature. The empirical work is based on a case study approach to research and focuses on an institution in Italy offering EFL courses for adult students. A multiple methods approach was adopted to investigate the problem and these included the use of focus groups, questionnaires, student compositions, direct classroom observations and a search of the Institution's documents relating to self-assessment and the Common European Framework of Reference for Languages: Learning, teaching, assessment (CEFR). Data were collected in three stages at intervals over a period of nine months.