In higher education, different disciplines have different prerequisites. Science, Technology, Engineering and Math (STEM) education often requires certain earlier course studies with specified grades in subjects such as mathematics and physics. In humanities, many research studies report on student failure due to insufficient second language skills in English. Fewer studies have reported on the importance of sufficient first language skills to cope with reading and writing in the intensive courses that are frequent in social science and humanities. The aim of this study is to investigate the potential relationship between students’ secondary school grades in their first language, and their learning outcomes in university programmes, given in the same language, at a department of education. The research question that guided this study was: what is the relationship between students’ grades in Swedish at secondary level and their level of completion of five-year university programmes. Data include N=2,583 unique students taking full teacher certification programmes at the university during 2016–2024 and was obtained and examined by SQLs from national databases Swedish Council for Higher Education and Ladok. Cross-mapping of data and basic statistical analysis, including linear multiple regression, was performed in SPSS. Results indicate that above average grade levels were connected with higher expected degree completion. A trend with increasingly higher grades in all admitted students during recent years was also observed. These results may concern educational stakeholders and policymakers that work with educational design and related implementations in university programmes. Implications from this study are further discussed, such as potential consequences of restricting university programmes to certain grade level prerequisites, and considerations to generic skills for degree completion of the students.