Micro, Small, and Medium Enterprises (MSMEs) play a pivotal role in Indonesia’s economy, accounting for more than 61% of national GDP and employing over 97% of the workforce. Nevertheless, intensifying global competition and the evolving behavior of digital consumers compel MSMEs to adopt advanced technologies. Among the emerging approaches, big data analytics has become increasingly relevant in supporting sustainable marketing decisions. This study investigates the extent to which MSMEs can harness big data to formulate effective and environmentally sustainable marketing strategies, employing the Structural Equation Modeling–Partial Least Square (SEM-PLS) method with data collected from 150 MSME respondents. The results reveal that big data exerts a significant influence on marketing decision-making and business sustainability. Moreover, digital marketing technologies positively moderate this relationship. The findings contribute empirical evidence that the adoption of big data not only improves marketing effectiveness but also fosters the long-term sustainability of MSMEs.