This article, written by Assistant Professor Noel Chia from the National Institute of Education, Nanyang Technological University, Singapore and Professor Stephen Houghton from the Centre for Child and Adolescent Related Disorders, University of Western Australia, reports an empirical evaluation of a one-year Orton-Gillingham instruction based reading intervention programme. The programme was conducted with 77 (61 male and 16 female) Singaporean primary school-aged children with dyslexia and a pre-test/post-test experimental group design was incorporated into a hybrid multiple baseline to inform analysis. A multivariate analysis of variance revealed a highly significant main effect for pre-post on the composite dependent variable made up of word recognition age (WRA), word expression age (WEA) and sentence reading age (SRA) scores. Univariate F tests revealed significant improvements in WRA and WEA. These effects were modest (7% and 8% variance accounted for, respectively) but high enough to be considered educationally significant. There was no main effect for SRA and no main effect as well as no significant interaction effect for teacher, indicating that teacher was not a moderating variable in the gains made on the subtests.