Examining the influence of adopting sustainability strategies on the competitiveness of five-star hotels operating in the State of Kuwait is the aim of this study. Sustainability strategies are represented by the responsibility towards four components, namely: the society, the employees, the environment, and the customers. The competitiveness variable is represented by hotels’ competitive advantage (cost, quality, flexibility, delivery, and creativity). The study is applied to the population of five-star hotels in the state of Kuwait (19 registered at the time of the study), and the final sample consisted of 294 hotel employees, and 360 hotel guests and customers totalling 654 observations. Responses were collected between November 2021 and January 2022 using an electronic questionnaire that was sent by email to hotels’ public relations managers for the hotel employees’ sample; and it was posted on several social media platforms and tourism forums for the customers’ sample. The findings indicate that five-star hotels in Kuwait are committed to sustainability implementation. The results of the regression model show a medium influential power of sustainability criteria in achieving a competitive advantage from both the employees’ and customers’ perspectives, indicating a statistical relationship between the variables. It is recommended that hotels should take advantage of the conclusions the study has reached in terms of the relationship between sustainability criteria and the achievement of a competitive advantage that would trigger favourable outcomes.