Abstract Childhood is a period characterized by a constant increase in sedentary time (ST) but also provides a great window of opportunity for children to learn how to limit ST. As a result, school-based interventions aimed at reducing and preventing children’s ST are increasingly becoming more widespread. A previous review found that school-based multi-component interventions appeared to be more effective in comparison to those based on a single component. However, this conclusion was based on just 11 studies published before 2016 and needs to be verified due to the currently growing number of studies on this topic. The objective of this systematic review is to update the evaluation of the effectiveness of school-based interventions published since the previous review according to the PRISMA guidelines. Studies published between August 2015 and August 2023 containing objective measures of ST were analyzed. Of the 18 studies identified, 11 (61.1%) reported significant positive results. Multi-component studies were slightly more effective than their single-component equivalent (63.7% vs. 57.1%). The components that proved the most effective of the multi-component studies were the implementation of sit-to-stand desks (100%), and teachers’ training (77.8%). The combination of these two components is the most promising method to limit ST in the school context. Future research should determine how sit-to-stand desks can be introduced into the class environment and how courses can be adapted to this material.