In the context of the increasing urgency for sustainable agricultural development, the circular economy is considered an effective approach. This study evaluates the effectiveness of a training program on circular economy practices, focusing on four key topics: organic composting, earthworm farming, vegetable cultivation using organic compost, and biological bedding systems. The study employs a pre-post design with 59 farming households surveyed using semi-structured questionnaires. Data were analyzed using descriptive statistics, the McNemar test for binary variables, and the Wilcoxon signed-rank test for ordinal scales. The results indicate that the training program generated positive and statistically significant impacts on farmers’ knowledge, skills, attitudes, and overall capacity. Novelty of this study lies in its quantitative assessment of circular economy training impacts based on an integrated capacity framework in a mountainous context, thereby providing empirical evidence and policy-relevant insights for agricultural extension and the scaling up of circular economy practices in disadvantaged areas.