This study investigates the factors influencing millennials' green purchase behavior (GPB) in Saudi Arabia, using the Theory of Planned Behavior (TPB) as a theoretical framework. A survey of 1094 students from King Faisal University was conducted, and data were analyzed using SmartPLS-3.3.2. The results indicate that green behavioral control (GBC), green environmental awareness (GEA), and green product value (GPV) have positive and significant effects on GPB. In contrast, green product trust (GPT), green price sensitivity (GPS), and green perceived quality (GPQ) do not significantly affect GPB. These findings highlight the importance of GBC, GEA, and GPV in shaping millennials' GPB, offering valuable insights for researchers, marketers, and policymakers. The study also suggests that future research should focus on cross-sectional studies to enhance the generalizability of the findings. The results contribute to the understanding of GPB in emerging markets, particularly in Saudi Arabia, and emphasize the need for further research on the factors influencing green purchase behavior in this context. The study underscores the significance of environmental awareness, behavioral control, and product value in driving millennials' green purchasing decisions.This study investigates the factors influencing millennials' green purchase behavior (GPB) in Saudi Arabia, using the Theory of Planned Behavior (TPB) as a theoretical framework. A survey of 1094 students from King Faisal University was conducted, and data were analyzed using SmartPLS-3.3.2. The results indicate that green behavioral control (GBC), green environmental awareness (GEA), and green product value (GPV) have positive and significant effects on GPB. In contrast, green product trust (GPT), green price sensitivity (GPS), and green perceived quality (GPQ) do not significantly affect GPB. These findings highlight the importance of GBC, GEA, and GPV in shaping millennials' GPB, offering valuable insights for researchers, marketers, and policymakers. The study also suggests that future research should focus on cross-sectional studies to enhance the generalizability of the findings. The results contribute to the understanding of GPB in emerging markets, particularly in Saudi Arabia, and emphasize the need for further research on the factors influencing green purchase behavior in this context. The study underscores the significance of environmental awareness, behavioral control, and product value in driving millennials' green purchasing decisions.