This study investigates the role of social media influence in fostering the adoption of sustainable fashion in Indonesia through the Stimulus-Organism-Response (S-O-R) framework. Specifically, it examines how social media influence shapes psychological mechanisms—pro-environmental attitudes, environmental guilt, and perceived longevity—while evaluating the moderating effect of financial constraints on the relationship between intention to switch and behavioral switching. Employing a quantitative approach, data were gathered from 306 respondents via online surveys and analyzed using Structural Equation Modeling-Partial Least Squares (SEM-PLS). The findings reveal that social media influence significantly enhances proenvironmental attitudes, fosters environmental guilt, and strengthens perceived longevity, collectively driving the intention to switch. However, financial constraints substantially weaken the progression from intention to switch to behavioral switching, highlighting critical barriers in cost-sensitive markets like Indonesia. These results emphasize the pivotal role of psychological factors in promoting sustainable consumption behaviors amid economic challenges. The study contributes theoretical insights and practical strategies for advancing sustainable fashion adoption, addressing both psychological mechanisms and financial barriers. Limitations and directions for future research are also discussed.