This article reports on the South African results of a study to identify and explain relationships between some major factors associated with successful reading at Grade 5. With 11 official languages, educational policy in South Africa advocates an additive bilingualism model, and students in Grades 1 to 3 are taught in their mother tongue. Thereafter, the language of learning and teaching changes to a second language, which in most cases is English. With this complexity of issues, hierarchical linear modeling (HLM) was used to determine the effect of a number of explanatory variables at student and school level on reading achievement as outcome variable, while controlling for language using the South African Progress in International Reading Literacy Study (PIRLS) 2006 data. Utilizing Creemers' comprehensive model of educational effectiveness (Creemers & Reezigt, 1999) as theoretical point of departure, this article will focus on the results of an overall South African model with student- and school-level variables. (Contains 6 tables and 5 notes.)