E-commerce is deemed as the next potential source of growth for Thailand, but small and medium-sized enterprises (SMEs) are still behind in their utilization of e-commerce. This article uses the decision-makers, technological, organizational and environmental (DTOE) framework to examine the key e-commerce barriers and determinants in e-commerce utilization by Thai SMEs based on a survey of retail and food and beverage (F&B) service establishments in metropolitan Bangkok. This study aims to fill the research gap by examining the types of barriers that hinder e-commerce utilization by Thai SMEs in the F&B and retail services, as well as their key determinants. Unlike e-commerce adoption, e-commerce utilization can capture the full range of e-commerce engagement. The survey’s findings indicate that organizational barriers significantly inhibit e-commerce utilization. Estimations from the structural equation modelling (SEM) show that exports, e-commerce tools, government support, and internal and external e-commerce platforms can enhance e-commerce utilization. In addition, business-to-business (B2B) e-commerce can increase the exports of Thai SMEs, while older entrepreneurs and SMEs tend to neglect e-commerce. Evidence-based policy implications and suggestions are also discussed in this study to enhance e-commerce utilization for Thai SMEs.