The strong expansion and diversification of the tourism market has resulted in significant development of the tour operator business and strong links between tour operators and destinations. With its travel packages, tour operators greatly influence the tourism market trends and are able to significantly accelerate the process of branding a specific destination. Apart from tour operators specializations which favor small destinations developed only for certain niche markets, destinations also profit from tour operator initiatives and partnerships whose investments are targeted directly on destinations. Paper includes an analysis of two very different destinations, the established tourism destination Dubrovnik and Ljubljana – destination developed on the principle of sustainability. By analyzing the available data, it has been established that, contrary to the common opinion, the development of mass tourism in destinations is not a consequence of tour operators business, but rather a consequence of an unplanned and uncontrolled development of tourism. Ljubljana confirms the theories according to which planned and sustainable development of tourism is the key to quality development of destination. In those destinations tour operators may develop businesses without developing a risk of mass tourism. In the future one can expect further popularization of the principle of sustainability and implementation of the same in businesses of all destinations as well as in the business of tour operators. It is also believed that there will be further development of tailor-made travel packages in order to increase the quality of travel packages. Also, a rise of limitations which destinations bring for tour operators are likely to follow, in order for destinations to presserve its atractions in the long run.