This single-case study discusses literacy skills and self-efficacy development in English as an additional language learner with dyslexia, whose first language was Mandarin. The participant attended 12 one-to-one intervention sessions, during which he was taught basic reading and writing skills and strategies using the multisensory, structured and explicit approach. The sessions were video-recorded and used specific learning objectives and carefully planned word reading and spelling tasks. The data collected were both quantitative and qualitative, including, among others, pre- and post-tests, multiple assessments of retrieval of the words learnt during the intervention, and self-evaluation of the performance in word reading and spelling tasks and in future similar tasks. Both standardised and non-standardised tests were used. Findings suggest a positive effect of the intervention on both literacy skill development and self-efficacy beliefs; however, differences were observed in self-evaluation and specific skill development. Pedagogical implications of the findings are discussed.