A call for students to have a deeper understanding, so that they can make sense of and apply their learning to authentic situations, has reverberated in science teaching in the Philippines. In response, educators, teachers, and policymakers have embraced contextualization as a constructivist approach to bridging the gap between concepts and real-life experiences. Considering the popularity of this approach, it is imperative to examine the overall effectiveness of contextualization in improving students' achievement at all educational levels and in all science domains, compared to the traditional setup. By using a set of inclusion selection criteria, 10 Philippine-based studies conducted from 2017 to 2020 qualified to be included in a meta-analysis. Seven of the studies focused on the secondary level and three on tertiary level. Studies were extracted from several meta-search engines, namely Google Scholar, Science Direct, ERIC, and JSTOR; the search was facilitated by Harzing's Publish and Perish software. Statistical results from these studies were analyzed using Meta-Essentials, version 1.4, to calculate the effect sizes, to conduct subgroup and moderator analyses, and to determine publication bias. Contextualization is an approach to teaching science that could have a positive effect on students' achievement. The variables educational level and science domain were found to have no influence on student achievement. Contextualized instruction used various techniques to maximize achievement of learning outcomes. A further systematic review, covering a wider scope, must be conducted to examine indicators that may influence the implementation of contextualization in the teaching and learning process.