This study investigated the perceived usefulness and actual use of vocabulary learning strategies by Taiwanese learners of English as a foreign language and examined the relationship between strategy use and lexical competence. The participants were 452 entering freshmen from 10 English classes at a Taiwanese university. Schmitts (1997) taxonomy of vocabulary learning strategies was used to elicit the participants strategy use and perceptions of strategy usefulness, and Schmitts (2000) Vocabulary Levels Test was adopted to measure the participants’ vocabulary level. The results of the study revealed a positive relationship between the frequency of learners strategy use and their perceptions of the usefulness of these strategies and showed that learners with higher lexical competence employed vocabulary learning strategies more frequently and perceived them to be more useful. In particular, the results indicated that learners with higher vocabulary competence regarded social strategies as the least useful and used them the least, whereas learners with lower competence considered memory strategies to be the least useful and used them the least. The results indicated that strategies involving self-regulated learning and those requiring deeper mental processing including learning skills related to organizing, analyzing, making inferences and reasoning were associated with higher lexical competence.