<p>Against the backdrop of increasing global environmental challenges, enhancing environmental science competency for students is a key educational objective, yet traditional methods often fail to connect knowledge with practice. The Science, Technology, Society, and Environment (STSE) orientation is a potential solution, but empirical evidence of its effectiveness in Vietnam is limited. This study, therefore, quantitatively evaluates the impact of STSE-oriented teaching compared to the traditional method on the development of 8th-grade students’ competency to “Explain the impact of human interactions with Earth’s systems”. Using a quasi-experimental, pre-test/post-test design, 220 8th-grade students in Thai Nguyen city were assigned to an experimental group (<i>n</i> = 110) learning the “Density-Pressure” topic via 5 STSE projects, or a control group (<i>n</i> = 110) following the traditional method. Post-test results were compared using Analysis of Covariance (ANCOVA) to control for initial competency. The ANCOVA revealed a highly significant difference favoring the experimental group (<i>F</i>(1,217) = 24.684, <i>p</i> &lt; 0.001), with the STSE method accounting for 10.2% of the variance in outcomes (Partial Eta Squared = 0.102). A paired-samples t-test confirmed significant improvement only in the experimental group (<i>p</i> &lt; 0.001), with no significant change in the control group (<i>p</i> = 0.226). The study provides strong empirical evidence that implementing the STSE orientation is a significantly more effective strategy than traditional methods for enhancing students’ environmental science competency, strongly supporting its integration into the science curriculum to achieve the competency development goals of Vietnam’s general education program.</p>