Teaching English to non-native speakers encompasses two main approaches: English as a Second Language (ESL) and English as a Foreign Language (EFL). Though both aim to develop learner’s proficiency in English, they differ significantly in context, learner environment, and instructional objectives. ESL typically occurs in English-speaking countries, where learners require English for daily communication, integration, and survival. In contrast, EFL is taught in non-English-speaking countries, often within academic or professional frameworks, where learners have limited exposure to the language outside the classroom. These differences influence teaching methodologies, curriculum design and learner motivation. Understanding the distinctions between ESL and EFL is crucial for edicators to effectively address learner needs, adapt instructional strategies, and foster language acquisition. This paper explores the key characteristics, challenges and pedagogical implications of ESL and EFL, highlighting best practices for each context.