Recent studies emphasize the importance of learning science while considering multiple perspectives on environment, society, economy, and technology, which allows learners to relate what they do in the classroom to the world beyond. In this study, 68 12-year-old primary students from 1 Malaysian school were followed while they engaged in a science curriculum centered around 8 environment-related socio-scientific issues during a unit on the interaction among living things. The analysis shows that the informal reasoning skills of the students improved significantly. Progressive implementation of SSI activities encouraged students to use evidence-based decision-making, improving reasoning modes, and advancing reasoning levels.