This study is specifically designed to measure the effectiveness of Contextual Teaching and Learning (CTL) on the students’ scientific attitude and achievement in Natural Science among Junior school students in Pekanbaru, Indonesia. This quasi experiment involved some 215 Form VII students from three public schools, segregated based on their existing cognitive abilities. The CTL materials was developed by applying RANGKA strategy. Overall, the findings revealed that there is significant difference exist across experimental groups in terms of students’ achievement. However, there is no significant difference in terms of scientific attitude. These findings contribute significant implications for the enhancement of scientific thinking skills among various students’ capabilities and different categories of school. Contextual teaching strategy is found appropriate in achieving the above dimensions in heterogeneous schools. This is due to the fact that the RANGKA contextual learning strategy as developed in this study focuses on the right way for students to learn.