Vocabulary acquisition is one of the most challenging obstacles language learners must overcome. This is especially true for students in English specialized classes where comprehension of academic texts is required. This minor thesis investigates the vocabulary strategy teaching component of an advanced-level course book for students in the grade 11th of Chu Van An High School. It first describes the course and the issues which prompted the study. The present study is an effort that aims to examine the students’ usage of vocabulary learning strategies that occurs as the course progresses and to analyse the development of passive and active vocabularies over a three-month period. It then reviews the literature relevant to the topic of research which serves as a theoretical for framework for the study. The data were collected by means of questionnaires and interviews. Results showed that students employed some certain determination, social, memory, cognitive and metacognitive strategies during the course. However, the frequency of determination strategies use was significantly higher than that of social and metacognive ones. The findings emphasize the potential influence of these strategies on the learners’ vocabulary development. Particularly, this study can claim to have achieved its goal of measuring improvements in students’ passive vocabularies and matching them to suitable targets after a three-month period. However, the findings from these studies have neither been completely sufficient nor consistent, which requires further research into particular strategies employed by learners of different proficiency levels in varied contexts. The study has developmental implication for researchers and teachers. It provides a categorization scheme of vocabulary learning strategies that are applicable to other studies in this field. In addition, based on the findings, it suggests explicit instruction to improve the efficiency of teaching vocabulary strategies.