In the modern competitive scenario, all companies seek to understand how to achieve success. One of the keys to conquer/maintain market shares is sustainability, which is a hot topic of numerous studies that have focused on its use as a solution to obtain social, environmental, economic, and cultural benefits. To this end, the present work aims to identify the variables able to guide consumers towards the choice of sustainable restaurants through the conceptual extension of a theoretical model known in literature as Theory of Planned Behavior (TPB). The authors propose an Extended Theory of Planned Behavior (ETPB), consisting of seven variables: attitude; subjective norm; perceived behavioral control; perceived usefulness; curiosity; behavioral intention; and behavior. The authors used a quantitative approach based on the test of a Structural Equation Model (SEM). Overall, 1023 questionnaires were analyzed. The results of the analysis provided empirical evidence for the hypotheses formulated suggesting that attitude, subjective norm, perceived behavioral control, perceived usefulness, and curiosity affected the consumers’ behavioral intention to prefer sustainable restaurants and that behavioral intention affected their actual behavior. Based on what emerged from the analysis, the work could be understood as a useful tool for scholars and practitioners, suggesting interesting theoretical and managerial implications. In fact, on the one hand, it contributes to the enrichment of scientific literature related to the factors triggering human choices, and, on the other, it helps maximize the success of the restaurants by highlighting the levers to be actioned to improve business performances. However, the paper presents a main limit, linkable to the fact that, whilst the use of questionnaires represents an advantage in terms of sample size, on the other hand, it does not allow us to go deeper in understanding the reasons why people prefer restaurants that adopt sustainable practices.