<![CDATA[Strengthening environmental understanding and awareness among school community members is essential for supporting the implementation of the Adiwiyata Program and sustainable development. This study aimed to analyze changes in environmental understanding and awareness among school community members before and after participating in Adiwiyata training. A quantitative approach with a pre-experimental one-group pretest–posttest design was employed at SMA Pembangunan Laboratorium, Universitas Negeri Padang, Indonesia. The study involved 25 participants, consisting of teachers and students. Data were collected using a 32-item assessment instrument covering environmental knowledge, environmental learning, environmental participation, and environmentally oriented school culture. Data were analyzed using descriptive statistics, normalized gain (N-Gain), and a paired-samples t-test with SPSS software. The results revealed an increase in the mean score from 84.92 at pretest to 111.20 at posttest, representing a gain of 26.28 points (30.95%). The mean N-Gain was 0.736, indicating a high level of improvement, with 60% of participants classified in the high-gain category. The paired-samples t-test revealed a statistically significant difference between pretest and posttest scores, t(24) = 11.449, p < 0.001, with a very large effect size (Cohen's dz = 2.29). These findings suggest that Adiwiyata training has the potential to strengthen environmental understanding and awareness among school community members. Sustaining these improvements requires the integration of environmental education into classroom learning, active school community participation, continuous mentoring, and the development of an environmentally responsible school culture.]]>
