Although consumption is the cornerstone of economic growth, it is unquestionably one of the main reasons for the current degradation of the planet. Hence, it is necessary to understand consumers’ different perceptions and behaviors regarding sustainable goods, as the solution will inevitably involve changing behaviors and promoting more sustainable consumption. In light of the challenges posed by sustainability within the wine sector, namely issues related to climate change, chemical exposure, and the availability of water and energy, and considering the industry’s substantial environmental and social impacts, it is important to understand the factors influencing wine consumer behavior. This research explores sustainable wine consumption in Portugal. Based on a sample of 197 valid responses, collected in an online survey that took place from March 20 to April 30 of 2024, and applying the Theory of Planned Behavior (TPB) framework, the current study found that consumers’ intention to consume sustainable wine is influenced by their attitudes, subjective norms, and sustainability awareness. Regarding the individuals’ consumption of sustainable wine, this behavior is influenced by the intention to consume this wine, and by consumers’ perceived behavioral control. The results also concluded that individuals’ intention to consume sustainable wine is significantly different across marital status, professional occupation, level of education, and age. With these valuable insights, this study aimed to increase the available information on sustainable wine consumption, allowing different stakeholders, namely political decision makers, to develop and implement more efficient measures to promote sustainable wine consumption.