This article explores the effective teaching of English vocabulary for specific purposes (ESP), focusing on the challenges and strategies that cater to learners in specialized professional or academic fields such as medicine, business, or engineering. It highlights the importance of vocabulary instruction in ESP and its foundation in various language-learning theories, including the lexical approach, schema theory, and communicative language teaching. The article emphasizes the importance of needs analysis to identify relevant vocabulary, categorizing it into technical, semi-technical, and general vocabulary. It also outlines instructional strategies such as contextualized learning, task-based learning, and the use of collocations, multimedia resources, and corpus-based teaching. These methods help learners engage actively with specialized vocabulary, ensuring that they acquire language skills applicable to real-world professional communication. The article provides a comprehensive guide for educators seeking to improve their ESP vocabulary teaching practices, ensuring learners develop both the vocabulary knowledge and practical language skills necessary for success in their specific fields.