English is the international language of business and opens up many opportunities to non-native speakers. Teaching English as a Second Language (TESL) instructors provide a valuable service to immigrants in English-speaking countries. This free online course introduces the essential learning theories and practices needed to be a TESL instructor. The course details the needs of adult ESL learners, the learning styles of students, and how to facilitate intercultural communication in the classroom. Following this, it describes the activities and exercises that increase student comprehension of the English language. Finally it explains how to prepare for and conduct a lesson including creating a lesson plan,