The paper discusses the seasonality of tourism in the Republic of Croatia. The first part of the paper defines the concept of seasonality, which are the main causes and consequences of the same and how to solve them in the most painless way. Seasonality implies a high concentration of tourism demand in the summer of one year. Seasonality stands out as a major problem in Croatia and is unfortunately largely represented and regarded as a detrimental feature of demand. The causes of seasonality can be of a natural and institutional character. Natural causes are very pronounced in the Republic of Croatia due to the pleasant climatic conditions during 2 the summer months and the large amount of sunny hours and the fairly clear sea. Institutional causes are also of great importance because of, for example, school holidays, public holidays and similar. All such causes are suitable to the accumulation of large quantities of demand in a short period of time in the country, but this has consequences for productive future development. The consequences of seasonality are environmental, economic and socio-cultural. Furthermore, methods of suppressing seasonality are outlined for how best to act accordingly. The reduction of seasonality can be influenced by the promotion of various cultural content and attractions that may persist beyond the „seasonal“ months. The second part of the paper explains the seasonality in the Republic of Croatia to what extent it is represented, what effective methods are used to calculate and display the distribution of tourist arrivals through the months of the year.