Vocabulary has been accepted as an important aspect of language learning in many studies. In the light of these studies in literature, the purpose of the present study is to evaluate the general and academic lexical competence and performance of preparatory class students at School of Foreign Languages, Kütahya Dumlupinar University. Within this aim, the current study investigated the students' general and academic receptive and productive vocabulary knowledge and their interrelationships among each other. The participants of the study included 94 preparatory class students who were going to major at Department of English Language and Literature. Through multiple test technique, two different vocabulary tests, a writing task, and a speaking task were implemented. According to the results, the students had large general and academic vocabulary size and depth. However, they mostly preferred high frequency words more than low frequency words and academic words. Moreover, their scores in productive vocabulary were lower than their receptive vocabulary knowledge scores. Therefore, it was observed that they could not reflect their lexical competence in their lexical performance.