This document provides an introduction to English for Specific Purposes (ESP). It defines ESP as focusing on meeting the specific language needs of particular groups of learners, and divides it into English for Academic Purposes and English for Occupational Purposes. ESP has become increasingly important with the rise of vocational training worldwide and the use of English as a global language of communication. Courses should be designed based on learners' needs and use authentic materials from their field of study or work to teach relevant vocabulary, discourse and skills.