The author contends that the topical content of ESL lesson materials in schools and universities is of ethical significance. Based on an established model for ethical judgment in social services, five guidelines for ethical selection of lesson topics are proposed and illustrated. Lesson topics must help ESL students: (a) adjust to local surroundings, (b) appreciate unfamiliar learning strategies, (c) explore genuine interests, (d) embrace institutional standards of conduct, and (e) foster mutual acceptance in the face of conflicting perspectives. After highlighting the benefits of applying these guidelines, the article calls for further refinement of this set of guidelines.