Since 1990, both people’s recognition of the need for sustainability around the world and environmental management systems in the tourism industry have been growing. Academic studies have primarily focused on the willingness of consumers to pay more to stay in major hotel chains, finding that the incorporation of environmental management systems (EMSs) is a way to save money by reducing costs, while improving the image and competitive advantage of these chains in the market. However, the aggregate environmental impact of tourism activity does not only depend on the practices of industry leaders. It also relates to the degree to which all stakeholders adopt these practices. Boutique hotels fall under the category of small-sized accommodation and are characterized by their size, independent management, and respect for the local environment. Hotel consumers display positive attitudes with respect to green hotel practices, which provides a starting point for motivating hotels to continue working on improving their environmental impact performance. For this reason, the objective of this paper is to determine whether boutique hotel clients are willing to pay more for a hotel with an environmental management system. Two dependence techniques are applied, logit regression and linear regression. The results show that the respondents’ age and income, as well as the strength of their environmental commitment, are determinant factors of whether clients would pay more to stay in a boutique hotel with an EMS. This preliminary study tries to investigate the “willingness to pay” in the Spanish boutique hotels. The originality of this article responds to the demand for a more holistic perspective on the hospitality sector, contributing to the understanding of hotel clients and their willingness to pay more for an EMS.