This document discusses assessing language learning strategy use through self-report scales. It describes the Strategy Inventory for Language Learning (SILL), the most widely used strategy scale. The SILL has high reliability across cultures and validity shown through links between higher scores and better language performance. Studies using the SILL in different cultures are discussed. Other strategy scales are also described, though many lacked reliability and validity data. In summary, the SILL is a reliable and valid tool for assessing language learning strategy use that has been widely applied in research worldwide.