Teacher reading content knowledge research spans decades and covers an array of issues from perceptions about knowledge to student achievement. Teacher reading content knowledge is developed during initial teacher education and extended through professional development, as it has been identified as an integral component of quality teaching and national teacher standards. However, despite this recognition, to date there is limited understanding about how teacher reading content knowledge is operationalized in early years classrooms for teaching children how to read. Since children’s proficiency in reading is developed during the first three years of schooling and teachers have the biggest influence on their learning, it seems logical that research would provide evidence about what reading content is taught in the early years of formal schooling, and how it is taught.   The aim of this thesis is to examine the teaching of reading by teachers classified as having different levels of teacher reading content knowledge. The analysis was undertaken with three separate but related studies. The first involved measuring teachers’ reading content knowledge and validating the measure, to identify teachers with varying levels of reading content knowledge. The second and third studies used a mixed-methods approach to analyze the differences in what and how reading was taught in the classrooms of teachers identified as having high and low levels of teacher reading content knowledge.   Findings from these studies provide quantitative and qualitative insights into the different ways teachers with high and low levels of teacher reading content knowledge teach reading. Teachers with high levels of reading content knowledge taught all aspects of the science of reading supported with pedagogical interactions that encouraged children to take risks by thinking beyond facts, as learning was based on need and moved from a surface to deep level. Whereas teachers with low levels of reading content knowledge taught all aspects of the science of reading apart from morphology. This teaching reinforced pedagogical interactions that developed child dependency and elicited factual and literal understanding to allow the teacher to move through the lesson. Results from these studies were outlined in terms of their practical implications, which suggest the need to establish minimum levels of teacher reading content knowledge and the development of preservice and in-services courses that helps teachers achieve these levels.