This study explores the relationship between sustainable practices in the hospitality industry, customer perceptions of these practices, and the role of customer reviews in evaluating sustainability. Leveraging a large dataset of hotel reviews from TripAdvisor, sentiment analysis and natural language processing techniques were employed to assess the impact of sustainability initiatives on guest satisfaction and hotel ratings. The data was collected from 2006 to 2023, analyzing approximately 1.4 million reviews from 3000 hotels in London and Paris. Sustainability-related keywords, such as “eco-friendly,” “green,” and “energy efficiency,” were used, and sentiment was measured using the sentimentr package in R. The findings reveal that positive sentiment in sustainability reviews is significantly associated with higher overall review ratings and hotel ratings, underscoring the strategic importance of sustainability practices. The analysis also highlights the evolving trends in review length and content, indicating a broader shift toward more concise feedback while maintaining detailed discussions on sustainability topics. Sustainability reviews tend to be longer and more detailed, reflecting the complexity and importance of these issues to guests. The implications for hotel management include the need to invest in visible and tangible sustainability efforts, effectively communicate these initiatives, and leverage customer feedback to enhance sustainability practices. This study contributes to the growing body of literature on sustainable tourism by providing empirical evidence of the positive impact of sustainability on guest satisfaction and hotel performance.