In the study of complexity, accuracy and fluency (CAF), syntactic complexity can be measured by a multitude of measures. Traditionally, the measures are quantitative and they use production units such as words, clauses, T -units, and sentences. Despite the vast number o f measures available, many studies have used only one or two of them, or parallel ones tapping the same component of complexity. The present study explores syntactic complexity using seven frequently used quantitative complexity measures to gauge different facets of complexity in written learner Finnish. The data of the study consist of texts written by adult and adolescent language learners, and they cover proficiency levels from beginner (A1) to advanced learner (C2) in the Common European Framework of Re ference (CEFR). According to the results, changes in the measures are not linear from one proficiency level to the next. The results also show that while all the selected measures catch some statistically significant differences between proficiency levels in adult language learner texts, only four measures do so in adolescent language learner texts. The results also suggest that the measures are sensitive to task type.