One of the effective and affordable ways to organize recreation and leisure in modern conditions is considered to be mass tourism, which is influenced by global trends: globalization, informatization, geopolitics. In the article, based on generalizations of the approaches of domestic and foreign researchers, an attempt is made to give a detailed definition of the term “mass tourism” and to specify its phenomenon through the justification of its distinctive features: the number of consumers (mass), motives and goals, the influence of technological progress, industrialization and scaling of the tourism business. The authors highlight factors contributing to the development of modern tourism, including: accessibility, globalization, marketing and advertising, political situation, economic stability, digitalization and conceptual approaches to the emergence and development of mass tourism: the theory of consumer society, the theory of mobile sociology, “quality tourism” and etc. Among the general principles of modern mass tourism, the authors highlight: the commercial principle of a balance of interests, taking into account the global problems facing humanity, the active socialization of tourism. Particular attention is paid to the issues of periodization of the formation of mass tourism in the historiography of various countries; description of the modern understanding of mass tourism, taking into account its influence on national socio-economic systems; determining the main directions for the development of mass tourism in the domestic market of tourism services, taking into account rapidly changing external conditions and factors, which made it possible to identify the main and most popular types of tourist activity.