This study examines the willingness of teachers and students to adopt the English-only instruction method in public secondary schools in the Western Senatorial Zone of Zamfara State, Nigeria. The study is motivated by concerns about the effectiveness of English-only instruction in a multilingual environment where many learners have limited exposure to English outside the classroom. A mixed-methods research design was adopted, involving two hundred (200) students and twenty (20) teachers selected from twenty (20) public secondary schools, comprising ten (10) rural and ten (10) urban schools. Data were collected through questionnaires containing closed-ended questions and opportunities for respondents to provide reasons for their responses. The quantitative data were analysed using frequencies and percentages, while the qualitative responses were examined thematically. The findings show that students recorded 1,399 “yes” responses compared with 640 “no” responses, while teachers recorded 208 “yes” responses compared with 147 “no” responses. The findings therefore indicate a generally positive attitude towards English-only instruction among the respondents. However, the responses also reveal challenges relating to students’ comprehension, limited English proficiency, inadequate teacher training, insufficient instructional materials, and the need for alternative teaching strategies. The study concludes that although English-only instruction is generally supported by teachers and students, its effective implementation requires adequate pedagogical support and sensitivity to learners’ linguistic backgrounds. It recommends regular teacher training, provision of adequate teaching and learning materials, and appropriate instructional strategies to support students with different levels of English proficiency.