This dissertation aims to solve a scientific problem – to determine what the theoretical preconditions for the development of the tourism sector (competitive advantages) are, and how the development of the tourism sector can be modelled to increasing the competitiveness of tourism regions in the context of sustainable development. The dissertation theoretically analyzes the problems of tourism sector development management in the context of sustainability and the competitiveness of tourism regions, distinguishing the factors of tourism region competitiveness, prepares a model of tourism sector development trends, increasing the competitiveness of tourism regions in the context of sustainable development. Based on theoretical and empirical research, a model of the Lithuanian tourism sector development trends increasing the competitiveness of tourism regions in the context of sustainable development is presented. The doctoral dissertation identifies trends in the development of the Lithuanian tourism sector in the context of sustainable development, which are modelled through the management enabling the transformation of the tourism sector, the growth of domestic tourism, the increasing mobility of the society, and the strengthening of the resilience of the tourism sector.