Research on third-language learning (L3) has documented that plurilingualism is an asset in many respects. Particularly relevant for this study is research showing that L3 learners use more strategies more frequently and efficiently than L2 learners. However, previous studies have mainly concentrated on L3 learners' strategy use at the university level, whereas little attention has been given to L3 learners in a secondary school context. This study investigated reports of strategy use by 127 L2-English and 104 L3-German learners who studied these two languages in Norwegian secondary schools. The results showed that L3-German school learners reported using significantly fewer strategies and applying them less frequently than L2-English school learners. It is hypothesized (a) that L3 learners may be insufficiently aware of how to transfer knowledge from previous language-learning experiences and (b) that L3 learners use fewer strategies than L2 learners due to lower motivation for learning L3 German than for learning L2 English.