Purpose: This study investigated the integration of Phenomenon-Based Learning (PhenoBL) and Geographic Information Systems (GIS) to enhance geo-literacy and student engagement among Grade 8 students in Thailand, addressing the gap in research on their combined impact in secondary geography teaching within the Thai educational context. Methods: The study implemented three iterative cycles over eight weeks through an action research design, with 30 students aged 13-14. The intervention focused on urbanization and environmental sustainability, utilizing Google Maps as a GIS tool for spatial analysis. Data collection included geo-literacy tests, student engagement surveys, and classroom observations, which were analyzed through paired t-tests and Pearson correlation analyses. Results: Findings demonstrated significant improvements in geo-literacy scores (from 59.5% to 72.5%, p < 0.01) and increases across all engagement dimensions (behavioral, emotional, and cognitive). Correlation analyses revealed a significant positive relationship between emotional engagement and geo-literacy improvement (r = 0.309, p < 0.05), while behavioral and cognitive engagement showed no significant correlations with geo-literacy gains. Conclusion: The emotional connection to learning activities is critical in geographic understanding. Qualitative observations documented students' progressive development of independence and confidence using GIS tools. These findings provide valuable insights for educators and policymakers implementing technology-enhanced, inquiry-based learning models in geography education while highlighting the importance of nurturing students' emotional engagement alongside structured support in GIS integration.