This study analyzes innovations in the hotel industry in the Republic of Serbia, focusing on how viral marketing contributes to the sustainability of this sector. The primary goal is to determine the impact of economic, environmental, and social aspects of sustainability on the sustainable principles of hotel business, and to investigate the moderating role of viral marketing and recommendations on tourists’ interest in visiting hotels that implement sustainable measures. The results showed that environmental, economic, social sustainability, and tourists’ interest have a significant positive impact on hotel sustainability. Viral marketing shows a strong impact on tourists’ interest but did not show a significant moderating effect on the sustainability of hotel business. Recommendations have shown a significant positive impact on tourists’ interest but did not show a direct impact on hotel sustainability. The findings highlight the importance of integrating sustainable practices and innovative marketing strategies to improve hotel sustainability and competitiveness.