This study aims to investigate the factors influencing the adoption intention of plant-based food products and to examine the mediating effects on the relationship between adoption intention and actual behaviour. The research is based on the Theory of Planned Behavior (TPB) as the foundational theoretical framework. Convenience sampling has been applied for data collection through an online questionnaire (G-Form), resulting in 582 usable responses. The measurement model was analyzed using Confirmatory Factor Analysis (CFA), and the structural equation model was assessed using Structural Equation Modeling (SEM). The findings indicate that factors positively influencing the adoption intention include attitudes towards plant-based food products, subjective norms, environmental concerns. Word-of-mouth communication was identified as a mediating variable in the relationship between adoption intention and actual behaviour. This research corroborates the Theory of Planned Behavior. Also, it identifies additional factors relevant to the acceptance of plant-based food products beyond the theoretical framework in Thailand. The findings provide valuable insights for business and marketing strategies about plant-based food products.