The Learning League project aims to study the improvement of language self-efficacy among English as a foreign language (EFL) university students in Hong Kong after delivery English language classes to secondary school students in a 12-week programme. The project adopts a blended learning approach, utilizing the learning-by-teaching pedagogy and gamification to enhance students' motivation and English speaking skills. 13 university students were recruited as student tutors. They received teaching training before teaching English to 63 secondary school students. English speaking-related weekly tasks and selected materials were provided to the student tutors to complete and read before they taught. The language self-efficacy of university students were measured using language self-efficacy scale (Wong, 2005). The programme evaluation showed positive results for the university students' English speaking skills and language self-efficacy. © 2023 International Conference on Higher Education Advances. All rights reserved.