This study investigated whether instructional materials determined English reading literacy of pupils in UPE Schools in Fort Portal Municipality in Uganda. The objectives of the study were to assess whether audio-visual instructional materials, graphic instructional materials and realia instructional materials determine the variation in pupils reading literacy in primary schools. The study adopted the quantitative approach only using an experimental research design on a sample of 327 pupils. An English reading test with question items on audio-visual, graphic and realia instructional materials was administered on pupils. Data were analysed using Student’s t – test. The results revealed that audio-visual, graphic and realia instructional materials contributed to the variation in pupils’ English reading literacy in primary schools. Therefore, it was concluded that the use of audio-visual instructional materials, graphic instructional materials and realia instructional materials is imperative for pupils reading literacy in Primary Schools. It was thus recommended that the Ministry of Education, head teachers and proprietors of schools should help teachers in primary schools to emphasise the use of audio-visual instructional materials, graphic instructional materials and realia instructional materials in teaching English reading literacy to pupils in primary schools.