Background: Human behaviour contributes in a major way to global warming (GW), significantly adding to ill-health and disease. As a result, efforts should be made to enlist the support of school-aged children in preventive behaviour. Objective: The aim of this study was to identify the effects of a school-network intervention using Reduce, Reuse and Recycle (3Rs) to improve primary students' GW preventive behaviour. Methods: A quasi-experimental pre-post and control group study was conducted. The experimental group (n = 359) and the comparison group (n = 331) comprising fifth and sixth grade primary students. School network members (SNMs), who included school principals, teachers, parents and community leaders, worked with the pupils for 4 months using the 3Rs approach. Data were collected by means of a self-administered questionnaire measuring knowledge, attitudes and practices. A paired t-test and an independent t-test were used to analyse the data. In-depth interviews and focus groups took place with SNMs to assess the perceived effectiveness of the 3Rs intervention. Results: Significant post-intervention improvements in students' knowledge, attitudes and practice were found in the experimental group. The 3Rs programme received significant support from SNMs. Green living sub-projects including waste product recycling, planting, school energy conservation and changes in school lunch programmes to include more green food, were established by children. Conclusions: The 3Rs model, complemented by school networking, was perceived to have had a positive impact on students' GW prevention activities.