Grammatical complexity is a feature of more advanced learner writing and, thus, a common goal of language syllabi and a typical scoring component of several high-stakes exams. In this paper, the aim is to explore the influence of 29 grammatical complexity features and the variation of them on grading during a high-stakes EFL exam in Sweden by analysing a learner corpus of 142 graded example texts and 175 teacher graded texts. The graded example texts are graded by expert raters and included in the assessment instructions as benchmarks that should guide teachers in the assessment of their own students’ texts. The results show that Of phrases had the clearest positive relationship with grade in texts assessed by expert raters and teachers. In contrast, verb + that complement clauses had a negative relationship with grade in the expert assessed texts, but not in the teacher assessed texts. Variation of grammatical complexity features had a positive relation with grade in the expert graded texts. The findings have implications for the design of EFL testing and teaching in Sweden, but also contribute to on-going discussions regarding design of high-stakes exams, language syllabi, and writing teaching pedagogy.