This descriptive quantitative study intended to investigate (1) the language learning strategies used by learners of English as a foreign language, (2) to find out the difference in their strategy use and (3) the correlation of these strategies with students' academic achievement at university preparatory school situated in the western part of Turkey between 445 (168 male, 277 female) students participated in the study. An inventory about language learning strategies was used to gather data and all tests were run with SPSS 16.0. The results showed that students mostly use social and metacognitive strategies. Moreover, both successful and unsuccessful students use these two strategies while learning English as a foreign language. Lastly, while the correlation rate is high between metacognitive and social strategies regarding academic achievement, it is low between social and memory strategies.