The article is focused on the use of text mining and sentiment analysis of online reviews for securing a sustainable level of service quality in hotel operations. Previous studies focused mainly only on the concept extraction and customer needs and want identification. This study is using text and sentiment analysis of 3671 reviews collected from various booking and review sites during 2019 and interviews with general and HR managers. The results show that the drivers of high service quality evaluation are mainly the employees' training and development and creation of a sustainable workplace. The fluctuation of employees or a high proportion of part-time employees with a temporal commitment to the employer and a high level of stress is causing a lower level of service quality perception from costumers. Based on the results, education providers should build close cooperation with hoteliers to provide updated information and needed skills to their students, and hoteliers should focus on the creation of sustainable workplace with reduction of employee fluctuation. The training and development should be planned more than once per year, and the employees must be trained not only for standard procedures but as well in various other fields like stress management.