Academic vocabulary, an essential aspect of higher education, is becoming increasingly important for pupils to master as larger groups go on to university studies. There is however little research done on how well-prepared Swedish pupils deem themselves to be for the higher educational requirements in English as a foreign language and whether they are able to assess their vocabulary skills with any degree of accuracy. In this article, a mixed method approach was used to explore a group of pupils' (N=45) self-efficacy, and self-assessment with regards to vocabulary size and mastery using the Common European Framework of Reference for Languages (CEFR) proficiency scales. A vocabulary test was then administered and the results were compared to their self-assessments. A few follow up interviews were conducted to get a deeper understanding the pupils' reasoning. The results indicate that high performing pupils consider themselves well prepared for university studies but tend to overestimate their vocabulary skills, indicating that Swedish pupils may not meet the curriculum's goals of having developed a realistic view of their language level and competence.